angelovcom.net

customize-controls.js (291564B)

---

 /**
  * @output wp-admin/js/customize-controls.js
  */
 
 /* global _wpCustomizeHeader, _wpCustomizeBackground, _wpMediaViewsL10n, MediaElementPlayer, console, confirm */
 (function( exports, $ ){
 	var Container, focus, normalizedTransitionendEventName, api = wp.customize;
 
 	api.OverlayNotification = api.Notification.extend(/** @lends wp.customize.OverlayNotification.prototype */{
 
 		/**
 		 * Whether the notification should show a loading spinner.
 		 *
 		 * @since 4.9.0
 		 * @var {boolean}
 		 */
 		loading: false,
 
 		/**
 		 * A notification that is displayed in a full-screen overlay.
 		 *
 		 * @constructs wp.customize.OverlayNotification
 		 * @augments   wp.customize.Notification
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {string} code - Code.
 		 * @param {Object} params - Params.
 		 */
 		initialize: function( code, params ) {
 			var notification = this;
 			api.Notification.prototype.initialize.call( notification, code, params );
 			notification.containerClasses += ' notification-overlay';
 			if ( notification.loading ) {
 				notification.containerClasses += ' notification-loading';
 			}
 		},
 
 		/**
 		 * Render notification.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @return {jQuery} Notification container.
 		 */
 		render: function() {
 			var li = api.Notification.prototype.render.call( this );
 			li.on( 'keydown', _.bind( this.handleEscape, this ) );
 			return li;
 		},
 
 		/**
 		 * Stop propagation on escape key presses, but also dismiss notification if it is dismissible.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {jQuery.Event} event - Event.
 		 * @return {void}
 		 */
 		handleEscape: function( event ) {
 			var notification = this;
 			if ( 27 === event.which ) {
 				event.stopPropagation();
 				if ( notification.dismissible && notification.parent ) {
 					notification.parent.remove( notification.code );
 				}
 			}
 		}
 	});
 
 	api.Notifications = api.Values.extend(/** @lends wp.customize.Notifications.prototype */{
 
 		/**
 		 * Whether the alternative style should be used.
 		 *
 		 * @since 4.9.0
 		 * @type {boolean}
 		 */
 		alt: false,
 
 		/**
 		 * The default constructor for items of the collection.
 		 *
 		 * @since 4.9.0
 		 * @type {object}
 		 */
 		defaultConstructor: api.Notification,
 
 		/**
 		 * A collection of observable notifications.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @constructs wp.customize.Notifications
 		 * @augments   wp.customize.Values
 		 *
 		 * @param {Object}  options - Options.
 		 * @param {jQuery}  [options.container] - Container element for notifications. This can be injected later.
 		 * @param {boolean} [options.alt] - Whether alternative style should be used when rendering notifications.
 		 *
 		 * @return {void}
 		 */
 		initialize: function( options ) {
 			var collection = this;
 
 			api.Values.prototype.initialize.call( collection, options );
 
 			_.bindAll( collection, 'constrainFocus' );
 
 			// Keep track of the order in which the notifications were added for sorting purposes.
 			collection._addedIncrement = 0;
 			collection._addedOrder = {};
 
 			// Trigger change event when notification is added or removed.
 			collection.bind( 'add', function( notification ) {
 				collection.trigger( 'change', notification );
 			});
 			collection.bind( 'removed', function( notification ) {
 				collection.trigger( 'change', notification );
 			});
 		},
 
 		/**
 		 * Get the number of notifications added.
 		 *
 		 * @since 4.9.0
 		 * @return {number} Count of notifications.
 		 */
 		count: function() {
 			return _.size( this._value );
 		},
 
 		/**
 		 * Add notification to the collection.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {string|wp.customize.Notification} notification - Notification object to add. Alternatively code may be supplied, and in that case the second notificationObject argument must be supplied.
 		 * @param {wp.customize.Notification} [notificationObject] - Notification to add when first argument is the code string.
 		 * @return {wp.customize.Notification} Added notification (or existing instance if it was already added).
 		 */
 		add: function( notification, notificationObject ) {
 			var collection = this, code, instance;
 			if ( 'string' === typeof notification ) {
 				code = notification;
 				instance = notificationObject;
 			} else {
 				code = notification.code;
 				instance = notification;
 			}
 			if ( ! collection.has( code ) ) {
 				collection._addedIncrement += 1;
 				collection._addedOrder[ code ] = collection._addedIncrement;
 			}
 			return api.Values.prototype.add.call( collection, code, instance );
 		},
 
 		/**
 		 * Add notification to the collection.
 		 *
 		 * @since 4.9.0
 		 * @param {string} code - Notification code to remove.
 		 * @return {api.Notification} Added instance (or existing instance if it was already added).
 		 */
 		remove: function( code ) {
 			var collection = this;
 			delete collection._addedOrder[ code ];
 			return api.Values.prototype.remove.call( this, code );
 		},
 
 		/**
 		 * Get list of notifications.
 		 *
 		 * Notifications may be sorted by type followed by added time.
 		 *
 		 * @since 4.9.0
 		 * @param {Object}  args - Args.
 		 * @param {boolean} [args.sort=false] - Whether to return the notifications sorted.
 		 * @return {Array.<wp.customize.Notification>} Notifications.
 		 */
 		get: function( args ) {
 			var collection = this, notifications, errorTypePriorities, params;
 			notifications = _.values( collection._value );
 
 			params = _.extend(
 				{ sort: false },
 				args
 			);
 
 			if ( params.sort ) {
 				errorTypePriorities = { error: 4, warning: 3, success: 2, info: 1 };
 				notifications.sort( function( a, b ) {
 					var aPriority = 0, bPriority = 0;
 					if ( ! _.isUndefined( errorTypePriorities[ a.type ] ) ) {
 						aPriority = errorTypePriorities[ a.type ];
 					}
 					if ( ! _.isUndefined( errorTypePriorities[ b.type ] ) ) {
 						bPriority = errorTypePriorities[ b.type ];
 					}
 					if ( aPriority !== bPriority ) {
 						return bPriority - aPriority; // Show errors first.
 					}
 					return collection._addedOrder[ b.code ] - collection._addedOrder[ a.code ]; // Show newer notifications higher.
 				});
 			}
 
 			return notifications;
 		},
 
 		/**
 		 * Render notifications area.
 		 *
 		 * @since 4.9.0
 		 * @return {void}
 		 */
 		render: function() {
 			var collection = this,
 				notifications, hadOverlayNotification = false, hasOverlayNotification, overlayNotifications = [],
 				previousNotificationsByCode = {},
 				listElement, focusableElements;
 
 			// Short-circuit if there are no container to render into.
 			if ( ! collection.container || ! collection.container.length ) {
 				return;
 			}
 
 			notifications = collection.get( { sort: true } );
 			collection.container.toggle( 0 !== notifications.length );
 
 			// Short-circuit if there are no changes to the notifications.
 			if ( collection.container.is( collection.previousContainer ) && _.isEqual( notifications, collection.previousNotifications ) ) {
 				return;
 			}
 
 			// Make sure list is part of the container.
 			listElement = collection.container.children( 'ul' ).first();
 			if ( ! listElement.length ) {
 				listElement = $( '<ul></ul>' );
 				collection.container.append( listElement );
 			}
 
 			// Remove all notifications prior to re-rendering.
 			listElement.find( '> [data-code]' ).remove();
 
 			_.each( collection.previousNotifications, function( notification ) {
 				previousNotificationsByCode[ notification.code ] = notification;
 			});
 
 			// Add all notifications in the sorted order.
 			_.each( notifications, function( notification ) {
 				var notificationContainer;
 				if ( wp.a11y && ( ! previousNotificationsByCode[ notification.code ] || ! _.isEqual( notification.message, previousNotificationsByCode[ notification.code ].message ) ) ) {
 					wp.a11y.speak( notification.message, 'assertive' );
 				}
 				notificationContainer = $( notification.render() );
 				notification.container = notificationContainer;
 				listElement.append( notificationContainer ); // @todo Consider slideDown() as enhancement.
 
 				if ( notification.extended( api.OverlayNotification ) ) {
 					overlayNotifications.push( notification );
 				}
 			});
 			hasOverlayNotification = Boolean( overlayNotifications.length );
 
 			if ( collection.previousNotifications ) {
 				hadOverlayNotification = Boolean( _.find( collection.previousNotifications, function( notification ) {
 					return notification.extended( api.OverlayNotification );
 				} ) );
 			}
 
 			if ( hasOverlayNotification !== hadOverlayNotification ) {
 				$( document.body ).toggleClass( 'customize-loading', hasOverlayNotification );
 				collection.container.toggleClass( 'has-overlay-notifications', hasOverlayNotification );
 				if ( hasOverlayNotification ) {
 					collection.previousActiveElement = document.activeElement;
 					$( document ).on( 'keydown', collection.constrainFocus );
 				} else {
 					$( document ).off( 'keydown', collection.constrainFocus );
 				}
 			}
 
 			if ( hasOverlayNotification ) {
 				collection.focusContainer = overlayNotifications[ overlayNotifications.length - 1 ].container;
 				collection.focusContainer.prop( 'tabIndex', -1 );
 				focusableElements = collection.focusContainer.find( ':focusable' );
 				if ( focusableElements.length ) {
 					focusableElements.first().focus();
 				} else {
 					collection.focusContainer.focus();
 				}
 			} else if ( collection.previousActiveElement ) {
 				$( collection.previousActiveElement ).trigger( 'focus' );
 				collection.previousActiveElement = null;
 			}
 
 			collection.previousNotifications = notifications;
 			collection.previousContainer = collection.container;
 			collection.trigger( 'rendered' );
 		},
 
 		/**
 		 * Constrain focus on focus container.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {jQuery.Event} event - Event.
 		 * @return {void}
 		 */
 		constrainFocus: function constrainFocus( event ) {
 			var collection = this, focusableElements;
 
 			// Prevent keys from escaping.
 			event.stopPropagation();
 
 			if ( 9 !== event.which ) { // Tab key.
 				return;
 			}
 
 			focusableElements = collection.focusContainer.find( ':focusable' );
 			if ( 0 === focusableElements.length ) {
 				focusableElements = collection.focusContainer;
 			}
 
 			if ( ! $.contains( collection.focusContainer[0], event.target ) || ! $.contains( collection.focusContainer[0], document.activeElement ) ) {
 				event.preventDefault();
 				focusableElements.first().focus();
 			} else if ( focusableElements.last().is( event.target ) && ! event.shiftKey ) {
 				event.preventDefault();
 				focusableElements.first().focus();
 			} else if ( focusableElements.first().is( event.target ) && event.shiftKey ) {
 				event.preventDefault();
 				focusableElements.last().focus();
 			}
 		}
 	});
 
 	api.Setting = api.Value.extend(/** @lends wp.customize.Setting.prototype */{
 
 		/**
 		 * Default params.
 		 *
 		 * @since 4.9.0
 		 * @var {object}
 		 */
 		defaults: {
 			transport: 'refresh',
 			dirty: false
 		},
 
 		/**
 		 * A Customizer Setting.
 		 *
 		 * A setting is WordPress data (theme mod, option, menu, etc.) that the user can
 		 * draft changes to in the Customizer.
 		 *
 		 * @see PHP class WP_Customize_Setting.
 		 *
 		 * @constructs wp.customize.Setting
 		 * @augments   wp.customize.Value
 		 *
 		 * @since 3.4.0
 		 *
 		 * @param {string}  id                          - The setting ID.
 		 * @param {*}       value                       - The initial value of the setting.
 		 * @param {Object}  [options={}]                - Options.
 		 * @param {string}  [options.transport=refresh] - The transport to use for previewing. Supports 'refresh' and 'postMessage'.
 		 * @param {boolean} [options.dirty=false]       - Whether the setting should be considered initially dirty.
 		 * @param {Object}  [options.previewer]         - The Previewer instance to sync with. Defaults to wp.customize.previewer.
 		 */
 		initialize: function( id, value, options ) {
 			var setting = this, params;
 			params = _.extend(
 				{ previewer: api.previewer },
 				setting.defaults,
 				options || {}
 			);
 
 			api.Value.prototype.initialize.call( setting, value, params );
 
 			setting.id = id;
 			setting._dirty = params.dirty; // The _dirty property is what the Customizer reads from.
 			setting.notifications = new api.Notifications();
 
 			// Whenever the setting's value changes, refresh the preview.
 			setting.bind( setting.preview );
 		},
 
 		/**
 		 * Refresh the preview, respective of the setting's refresh policy.
 		 *
 		 * If the preview hasn't sent a keep-alive message and is likely
 		 * disconnected by having navigated to a non-allowed URL, then the
 		 * refresh transport will be forced when postMessage is the transport.
 		 * Note that postMessage does not throw an error when the recipient window
 		 * fails to match the origin window, so using try/catch around the
 		 * previewer.send() call to then fallback to refresh will not work.
 		 *
 		 * @since 3.4.0
 		 * @access public
 		 *
 		 * @return {void}
 		 */
 		preview: function() {
 			var setting = this, transport;
 			transport = setting.transport;
 
 			if ( 'postMessage' === transport && ! api.state( 'previewerAlive' ).get() ) {
 				transport = 'refresh';
 			}
 
 			if ( 'postMessage' === transport ) {
 				setting.previewer.send( 'setting', [ setting.id, setting() ] );
 			} else if ( 'refresh' === transport ) {
 				setting.previewer.refresh();
 			}
 		},
 
 		/**
 		 * Find controls associated with this setting.
 		 *
 		 * @since 4.6.0
 		 * @return {wp.customize.Control[]} Controls associated with setting.
 		 */
 		findControls: function() {
 			var setting = this, controls = [];
 			api.control.each( function( control ) {
 				_.each( control.settings, function( controlSetting ) {
 					if ( controlSetting.id === setting.id ) {
 						controls.push( control );
 					}
 				} );
 			} );
 			return controls;
 		}
 	});
 
 	/**
 	 * Current change count.
 	 *
 	 * @alias wp.customize._latestRevision
 	 *
 	 * @since 4.7.0
 	 * @type {number}
 	 * @protected
 	 */
 	api._latestRevision = 0;
 
 	/**
 	 * Last revision that was saved.
 	 *
 	 * @alias wp.customize._lastSavedRevision
 	 *
 	 * @since 4.7.0
 	 * @type {number}
 	 * @protected
 	 */
 	api._lastSavedRevision = 0;
 
 	/**
 	 * Latest revisions associated with the updated setting.
 	 *
 	 * @alias wp.customize._latestSettingRevisions
 	 *
 	 * @since 4.7.0
 	 * @type {object}
 	 * @protected
 	 */
 	api._latestSettingRevisions = {};
 
 	/*
 	 * Keep track of the revision associated with each updated setting so that
 	 * requestChangesetUpdate knows which dirty settings to include. Also, once
 	 * ready is triggered and all initial settings have been added, increment
 	 * revision for each newly-created initially-dirty setting so that it will
 	 * also be included in changeset update requests.
 	 */
 	api.bind( 'change', function incrementChangedSettingRevision( setting ) {
 		api._latestRevision += 1;
 		api._latestSettingRevisions[ setting.id ] = api._latestRevision;
 	} );
 	api.bind( 'ready', function() {
 		api.bind( 'add', function incrementCreatedSettingRevision( setting ) {
 			if ( setting._dirty ) {
 				api._latestRevision += 1;
 				api._latestSettingRevisions[ setting.id ] = api._latestRevision;
 			}
 		} );
 	} );
 
 	/**
 	 * Get the dirty setting values.
 	 *
 	 * @alias wp.customize.dirtyValues
 	 *
 	 * @since 4.7.0
 	 * @access public
 	 *
 	 * @param {Object} [options] Options.
 	 * @param {boolean} [options.unsaved=false] Whether only values not saved yet into a changeset will be returned (differential changes).
 	 * @return {Object} Dirty setting values.
 	 */
 	api.dirtyValues = function dirtyValues( options ) {
 		var values = {};
 		api.each( function( setting ) {
 			var settingRevision;
 
 			if ( ! setting._dirty ) {
 				return;
 			}
 
 			settingRevision = api._latestSettingRevisions[ setting.id ];
 
 			// Skip including settings that have already been included in the changeset, if only requesting unsaved.
 			if ( api.state( 'changesetStatus' ).get() && ( options && options.unsaved ) && ( _.isUndefined( settingRevision ) || settingRevision <= api._lastSavedRevision ) ) {
 				return;
 			}
 
 			values[ setting.id ] = setting.get();
 		} );
 		return values;
 	};
 
 	/**
 	 * Request updates to the changeset.
 	 *
 	 * @alias wp.customize.requestChangesetUpdate
 	 *
 	 * @since 4.7.0
 	 * @access public
 	 *
 	 * @param {Object}  [changes] - Mapping of setting IDs to setting params each normally including a value property, or mapping to null.
 	 *                             If not provided, then the changes will still be obtained from unsaved dirty settings.
 	 * @param {Object}  [args] - Additional options for the save request.
 	 * @param {boolean} [args.autosave=false] - Whether changes will be stored in autosave revision if the changeset has been promoted from an auto-draft.
 	 * @param {boolean} [args.force=false] - Send request to update even when there are no changes to submit. This can be used to request the latest status of the changeset on the server.
 	 * @param {string}  [args.title] - Title to update in the changeset. Optional.
 	 * @param {string}  [args.date] - Date to update in the changeset. Optional.
 	 * @return {jQuery.Promise} Promise resolving with the response data.
 	 */
 	api.requestChangesetUpdate = function requestChangesetUpdate( changes, args ) {
 		var deferred, request, submittedChanges = {}, data, submittedArgs;
 		deferred = new $.Deferred();
 
 		// Prevent attempting changeset update while request is being made.
 		if ( 0 !== api.state( 'processing' ).get() ) {
 			deferred.reject( 'already_processing' );
 			return deferred.promise();
 		}
 
 		submittedArgs = _.extend( {
 			title: null,
 			date: null,
 			autosave: false,
 			force: false
 		}, args );
 
 		if ( changes ) {
 			_.extend( submittedChanges, changes );
 		}
 
 		// Ensure all revised settings (changes pending save) are also included, but not if marked for deletion in changes.
 		_.each( api.dirtyValues( { unsaved: true } ), function( dirtyValue, settingId ) {
 			if ( ! changes || null !== changes[ settingId ] ) {
 				submittedChanges[ settingId ] = _.extend(
 					{},
 					submittedChanges[ settingId ] || {},
 					{ value: dirtyValue }
 				);
 			}
 		} );
 
 		// Allow plugins to attach additional params to the settings.
 		api.trigger( 'changeset-save', submittedChanges, submittedArgs );
 
 		// Short-circuit when there are no pending changes.
 		if ( ! submittedArgs.force && _.isEmpty( submittedChanges ) && null === submittedArgs.title && null === submittedArgs.date ) {
 			deferred.resolve( {} );
 			return deferred.promise();
 		}
 
 		// A status would cause a revision to be made, and for this wp.customize.previewer.save() should be used.
 		// Status is also disallowed for revisions regardless.
 		if ( submittedArgs.status ) {
 			return deferred.reject( { code: 'illegal_status_in_changeset_update' } ).promise();
 		}
 
 		// Dates not beung allowed for revisions are is a technical limitation of post revisions.
 		if ( submittedArgs.date && submittedArgs.autosave ) {
 			return deferred.reject( { code: 'illegal_autosave_with_date_gmt' } ).promise();
 		}
 
 		// Make sure that publishing a changeset waits for all changeset update requests to complete.
 		api.state( 'processing' ).set( api.state( 'processing' ).get() + 1 );
 		deferred.always( function() {
 			api.state( 'processing' ).set( api.state( 'processing' ).get() - 1 );
 		} );
 
 		// Ensure that if any plugins add data to save requests by extending query() that they get included here.
 		data = api.previewer.query( { excludeCustomizedSaved: true } );
 		delete data.customized; // Being sent in customize_changeset_data instead.
 		_.extend( data, {
 			nonce: api.settings.nonce.save,
 			customize_theme: api.settings.theme.stylesheet,
 			customize_changeset_data: JSON.stringify( submittedChanges )
 		} );
 		if ( null !== submittedArgs.title ) {
 			data.customize_changeset_title = submittedArgs.title;
 		}
 		if ( null !== submittedArgs.date ) {
 			data.customize_changeset_date = submittedArgs.date;
 		}
 		if ( false !== submittedArgs.autosave ) {
 			data.customize_changeset_autosave = 'true';
 		}
 
 		// Allow plugins to modify the params included with the save request.
 		api.trigger( 'save-request-params', data );
 
 		request = wp.ajax.post( 'customize_save', data );
 
 		request.done( function requestChangesetUpdateDone( data ) {
 			var savedChangesetValues = {};
 
 			// Ensure that all settings updated subsequently will be included in the next changeset update request.
 			api._lastSavedRevision = Math.max( api._latestRevision, api._lastSavedRevision );
 
 			api.state( 'changesetStatus' ).set( data.changeset_status );
 
 			if ( data.changeset_date ) {
 				api.state( 'changesetDate' ).set( data.changeset_date );
 			}
 
 			deferred.resolve( data );
 			api.trigger( 'changeset-saved', data );
 
 			if ( data.setting_validities ) {
 				_.each( data.setting_validities, function( validity, settingId ) {
 					if ( true === validity && _.isObject( submittedChanges[ settingId ] ) && ! _.isUndefined( submittedChanges[ settingId ].value ) ) {
 						savedChangesetValues[ settingId ] = submittedChanges[ settingId ].value;
 					}
 				} );
 			}
 
 			api.previewer.send( 'changeset-saved', _.extend( {}, data, { saved_changeset_values: savedChangesetValues } ) );
 		} );
 		request.fail( function requestChangesetUpdateFail( data ) {
 			deferred.reject( data );
 			api.trigger( 'changeset-error', data );
 		} );
 		request.always( function( data ) {
 			if ( data.setting_validities ) {
 				api._handleSettingValidities( {
 					settingValidities: data.setting_validities
 				} );
 			}
 		} );
 
 		return deferred.promise();
 	};
 
 	/**
 	 * Watch all changes to Value properties, and bubble changes to parent Values instance
 	 *
 	 * @alias wp.customize.utils.bubbleChildValueChanges
 	 *
 	 * @since 4.1.0
 	 *
 	 * @param {wp.customize.Class} instance
 	 * @param {Array}              properties  The names of the Value instances to watch.
 	 */
 	api.utils.bubbleChildValueChanges = function ( instance, properties ) {
 		$.each( properties, function ( i, key ) {
 			instance[ key ].bind( function ( to, from ) {
 				if ( instance.parent && to !== from ) {
 					instance.parent.trigger( 'change', instance );
 				}
 			} );
 		} );
 	};
 
 	/**
 	 * Expand a panel, section, or control and focus on the first focusable element.
 	 *
 	 * @alias wp.customize~focus
 	 *
 	 * @since 4.1.0
 	 *
 	 * @param {Object}   [params]
 	 * @param {Function} [params.completeCallback]
 	 */
 	focus = function ( params ) {
 		var construct, completeCallback, focus, focusElement;
 		construct = this;
 		params = params || {};
 		focus = function () {
 			var focusContainer;
 			if ( ( construct.extended( api.Panel ) || construct.extended( api.Section ) ) && construct.expanded && construct.expanded() ) {
 				focusContainer = construct.contentContainer;
 			} else {
 				focusContainer = construct.container;
 			}
 
 			focusElement = focusContainer.find( '.control-focus:first' );
 			if ( 0 === focusElement.length ) {
 				// Note that we can't use :focusable due to a jQuery UI issue. See: https://github.com/jquery/jquery-ui/pull/1583
 				focusElement = focusContainer.find( 'input, select, textarea, button, object, a[href], [tabindex]' ).filter( ':visible' ).first();
 			}
 			focusElement.focus();
 		};
 		if ( params.completeCallback ) {
 			completeCallback = params.completeCallback;
 			params.completeCallback = function () {
 				focus();
 				completeCallback();
 			};
 		} else {
 			params.completeCallback = focus;
 		}
 
 		api.state( 'paneVisible' ).set( true );
 		if ( construct.expand ) {
 			construct.expand( params );
 		} else {
 			params.completeCallback();
 		}
 	};
 
 	/**
 	 * Stable sort for Panels, Sections, and Controls.
 	 *
 	 * If a.priority() === b.priority(), then sort by their respective params.instanceNumber.
 	 *
 	 * @alias wp.customize.utils.prioritySort
 	 *
 	 * @since 4.1.0
 	 *
 	 * @param {(wp.customize.Panel|wp.customize.Section|wp.customize.Control)} a
 	 * @param {(wp.customize.Panel|wp.customize.Section|wp.customize.Control)} b
 	 * @return {number}
 	 */
 	api.utils.prioritySort = function ( a, b ) {
 		if ( a.priority() === b.priority() && typeof a.params.instanceNumber === 'number' && typeof b.params.instanceNumber === 'number' ) {
 			return a.params.instanceNumber - b.params.instanceNumber;
 		} else {
 			return a.priority() - b.priority();
 		}
 	};
 
 	/**
 	 * Return whether the supplied Event object is for a keydown event but not the Enter key.
 	 *
 	 * @alias wp.customize.utils.isKeydownButNotEnterEvent
 	 *
 	 * @since 4.1.0
 	 *
 	 * @param {jQuery.Event} event
 	 * @return {boolean}
 	 */
 	api.utils.isKeydownButNotEnterEvent = function ( event ) {
 		return ( 'keydown' === event.type && 13 !== event.which );
 	};
 
 	/**
 	 * Return whether the two lists of elements are the same and are in the same order.
 	 *
 	 * @alias wp.customize.utils.areElementListsEqual
 	 *
 	 * @since 4.1.0
 	 *
 	 * @param {Array|jQuery} listA
 	 * @param {Array|jQuery} listB
 	 * @return {boolean}
 	 */
 	api.utils.areElementListsEqual = function ( listA, listB ) {
 		var equal = (
 			listA.length === listB.length && // If lists are different lengths, then naturally they are not equal.
 			-1 === _.indexOf( _.map(         // Are there any false values in the list returned by map?
 				_.zip( listA, listB ),       // Pair up each element between the two lists.
 				function ( pair ) {
 					return $( pair[0] ).is( pair[1] ); // Compare to see if each pair is equal.
 				}
 			), false ) // Check for presence of false in map's return value.
 		);
 		return equal;
 	};
 
 	/**
 	 * Highlight the existence of a button.
 	 *
 	 * This function reminds the user of a button represented by the specified
 	 * UI element, after an optional delay. If the user focuses the element
 	 * before the delay passes, the reminder is canceled.
 	 *
 	 * @alias wp.customize.utils.highlightButton
 	 *
 	 * @since 4.9.0
 	 *
 	 * @param {jQuery} button - The element to highlight.
 	 * @param {Object} [options] - Options.
 	 * @param {number} [options.delay=0] - Delay in milliseconds.
 	 * @param {jQuery} [options.focusTarget] - A target for user focus that defaults to the highlighted element.
 	 *                                         If the user focuses the target before the delay passes, the reminder
 	 *                                         is canceled. This option exists to accommodate compound buttons
 	 *                                         containing auxiliary UI, such as the Publish button augmented with a
 	 *                                         Settings button.
 	 * @return {Function} An idempotent function that cancels the reminder.
 	 */
 	api.utils.highlightButton = function highlightButton( button, options ) {
 		var animationClass = 'button-see-me',
 			canceled = false,
 			params;
 
 		params = _.extend(
 			{
 				delay: 0,
 				focusTarget: button
 			},
 			options
 		);
 
 		function cancelReminder() {
 			canceled = true;
 		}
 
 		params.focusTarget.on( 'focusin', cancelReminder );
 		setTimeout( function() {
 			params.focusTarget.off( 'focusin', cancelReminder );
 
 			if ( ! canceled ) {
 				button.addClass( animationClass );
 				button.one( 'animationend', function() {
 					/*
 					 * Remove animation class to avoid situations in Customizer where
 					 * DOM nodes are moved (re-inserted) and the animation repeats.
 					 */
 					button.removeClass( animationClass );
 				} );
 			}
 		}, params.delay );
 
 		return cancelReminder;
 	};
 
 	/**
 	 * Get current timestamp adjusted for server clock time.
 	 *
 	 * Same functionality as the `current_time( 'mysql', false )` function in PHP.
 	 *
 	 * @alias wp.customize.utils.getCurrentTimestamp
 	 *
 	 * @since 4.9.0
 	 *
 	 * @return {number} Current timestamp.
 	 */
 	api.utils.getCurrentTimestamp = function getCurrentTimestamp() {
 		var currentDate, currentClientTimestamp, timestampDifferential;
 		currentClientTimestamp = _.now();
 		currentDate = new Date( api.settings.initialServerDate.replace( /-/g, '/' ) );
 		timestampDifferential = currentClientTimestamp - api.settings.initialClientTimestamp;
 		timestampDifferential += api.settings.initialClientTimestamp - api.settings.initialServerTimestamp;
 		currentDate.setTime( currentDate.getTime() + timestampDifferential );
 		return currentDate.getTime();
 	};
 
 	/**
 	 * Get remaining time of when the date is set.
 	 *
 	 * @alias wp.customize.utils.getRemainingTime
 	 *
 	 * @since 4.9.0
 	 *
 	 * @param {string|number|Date} datetime - Date time or timestamp of the future date.
 	 * @return {number} remainingTime - Remaining time in milliseconds.
 	 */
 	api.utils.getRemainingTime = function getRemainingTime( datetime ) {
 		var millisecondsDivider = 1000, remainingTime, timestamp;
 		if ( datetime instanceof Date ) {
 			timestamp = datetime.getTime();
 		} else if ( 'string' === typeof datetime ) {
 			timestamp = ( new Date( datetime.replace( /-/g, '/' ) ) ).getTime();
 		} else {
 			timestamp = datetime;
 		}
 
 		remainingTime = timestamp - api.utils.getCurrentTimestamp();
 		remainingTime = Math.ceil( remainingTime / millisecondsDivider );
 		return remainingTime;
 	};
 
 	/**
 	 * Return browser supported `transitionend` event name.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @ignore
 	 *
 	 * @return {string|null} Normalized `transitionend` event name or null if CSS transitions are not supported.
 	 */
 	normalizedTransitionendEventName = (function () {
 		var el, transitions, prop;
 		el = document.createElement( 'div' );
 		transitions = {
 			'transition'      : 'transitionend',
 			'OTransition'     : 'oTransitionEnd',
 			'MozTransition'   : 'transitionend',
 			'WebkitTransition': 'webkitTransitionEnd'
 		};
 		prop = _.find( _.keys( transitions ), function( prop ) {
 			return ! _.isUndefined( el.style[ prop ] );
 		} );
 		if ( prop ) {
 			return transitions[ prop ];
 		} else {
 			return null;
 		}
 	})();
 
 	Container = api.Class.extend(/** @lends wp.customize~Container.prototype */{
 		defaultActiveArguments: { duration: 'fast', completeCallback: $.noop },
 		defaultExpandedArguments: { duration: 'fast', completeCallback: $.noop },
 		containerType: 'container',
 		defaults: {
 			title: '',
 			description: '',
 			priority: 100,
 			type: 'default',
 			content: null,
 			active: true,
 			instanceNumber: null
 		},
 
 		/**
 		 * Base class for Panel and Section.
 		 *
 		 * @constructs wp.customize~Container
 		 * @augments   wp.customize.Class
 		 *
 		 * @since 4.1.0
 		 *
 		 * @borrows wp.customize~focus as focus
 		 *
 		 * @param {string}  id - The ID for the container.
 		 * @param {Object}  options - Object containing one property: params.
 		 * @param {string}  options.title - Title shown when panel is collapsed and expanded.
 		 * @param {string}  [options.description] - Description shown at the top of the panel.
 		 * @param {number}  [options.priority=100] - The sort priority for the panel.
 		 * @param {string}  [options.templateId] - Template selector for container.
 		 * @param {string}  [options.type=default] - The type of the panel. See wp.customize.panelConstructor.
 		 * @param {string}  [options.content] - The markup to be used for the panel container. If empty, a JS template is used.
 		 * @param {boolean} [options.active=true] - Whether the panel is active or not.
 		 * @param {Object}  [options.params] - Deprecated wrapper for the above properties.
 		 */
 		initialize: function ( id, options ) {
 			var container = this;
 			container.id = id;
 
 			if ( ! Container.instanceCounter ) {
 				Container.instanceCounter = 0;
 			}
 			Container.instanceCounter++;
 
 			$.extend( container, {
 				params: _.defaults(
 					options.params || options, // Passing the params is deprecated.
 					container.defaults
 				)
 			} );
 			if ( ! container.params.instanceNumber ) {
 				container.params.instanceNumber = Container.instanceCounter;
 			}
 			container.notifications = new api.Notifications();
 			container.templateSelector = container.params.templateId || 'customize-' + container.containerType + '-' + container.params.type;
 			container.container = $( container.params.content );
 			if ( 0 === container.container.length ) {
 				container.container = $( container.getContainer() );
 			}
 			container.headContainer = container.container;
 			container.contentContainer = container.getContent();
 			container.container = container.container.add( container.contentContainer );
 
 			container.deferred = {
 				embedded: new $.Deferred()
 			};
 			container.priority = new api.Value();
 			container.active = new api.Value();
 			container.activeArgumentsQueue = [];
 			container.expanded = new api.Value();
 			container.expandedArgumentsQueue = [];
 
 			container.active.bind( function ( active ) {
 				var args = container.activeArgumentsQueue.shift();
 				args = $.extend( {}, container.defaultActiveArguments, args );
 				active = ( active && container.isContextuallyActive() );
 				container.onChangeActive( active, args );
 			});
 			container.expanded.bind( function ( expanded ) {
 				var args = container.expandedArgumentsQueue.shift();
 				args = $.extend( {}, container.defaultExpandedArguments, args );
 				container.onChangeExpanded( expanded, args );
 			});
 
 			container.deferred.embedded.done( function () {
 				container.setupNotifications();
 				container.attachEvents();
 			});
 
 			api.utils.bubbleChildValueChanges( container, [ 'priority', 'active' ] );
 
 			container.priority.set( container.params.priority );
 			container.active.set( container.params.active );
 			container.expanded.set( false );
 		},
 
 		/**
 		 * Get the element that will contain the notifications.
 		 *
 		 * @since 4.9.0
 		 * @return {jQuery} Notification container element.
 		 */
 		getNotificationsContainerElement: function() {
 			var container = this;
 			return container.contentContainer.find( '.customize-control-notifications-container:first' );
 		},
 
 		/**
 		 * Set up notifications.
 		 *
 		 * @since 4.9.0
 		 * @return {void}
 		 */
 		setupNotifications: function() {
 			var container = this, renderNotifications;
 			container.notifications.container = container.getNotificationsContainerElement();
 
 			// Render notifications when they change and when the construct is expanded.
 			renderNotifications = function() {
 				if ( container.expanded.get() ) {
 					container.notifications.render();
 				}
 			};
 			container.expanded.bind( renderNotifications );
 			renderNotifications();
 			container.notifications.bind( 'change', _.debounce( renderNotifications ) );
 		},
 
 		/**
 		 * @since 4.1.0
 		 *
 		 * @abstract
 		 */
 		ready: function() {},
 
 		/**
 		 * Get the child models associated with this parent, sorting them by their priority Value.
 		 *
 		 * @since 4.1.0
 		 *
 		 * @param {string} parentType
 		 * @param {string} childType
 		 * @return {Array}
 		 */
 		_children: function ( parentType, childType ) {
 			var parent = this,
 				children = [];
 			api[ childType ].each( function ( child ) {
 				if ( child[ parentType ].get() === parent.id ) {
 					children.push( child );
 				}
 			} );
 			children.sort( api.utils.prioritySort );
 			return children;
 		},
 
 		/**
 		 * To override by subclass, to return whether the container has active children.
 		 *
 		 * @since 4.1.0
 		 *
 		 * @abstract
 		 */
 		isContextuallyActive: function () {
 			throw new Error( 'Container.isContextuallyActive() must be overridden in a subclass.' );
 		},
 
 		/**
 		 * Active state change handler.
 		 *
 		 * Shows the container if it is active, hides it if not.
 		 *
 		 * To override by subclass, update the container's UI to reflect the provided active state.
 		 *
 		 * @since 4.1.0
 		 *
 		 * @param {boolean}  active - The active state to transiution to.
 		 * @param {Object}   [args] - Args.
 		 * @param {Object}   [args.duration] - The duration for the slideUp/slideDown animation.
 		 * @param {boolean}  [args.unchanged] - Whether the state is already known to not be changed, and so short-circuit with calling completeCallback early.
 		 * @param {Function} [args.completeCallback] - Function to call when the slideUp/slideDown has completed.
 		 */
 		onChangeActive: function( active, args ) {
 			var construct = this,
 				headContainer = construct.headContainer,
 				duration, expandedOtherPanel;
 
 			if ( args.unchanged ) {
 				if ( args.completeCallback ) {
 					args.completeCallback();
 				}
 				return;
 			}
 
 			duration = ( 'resolved' === api.previewer.deferred.active.state() ? args.duration : 0 );
 
 			if ( construct.extended( api.Panel ) ) {
 				// If this is a panel is not currently expanded but another panel is expanded, do not animate.
 				api.panel.each(function ( panel ) {
 					if ( panel !== construct && panel.expanded() ) {
 						expandedOtherPanel = panel;
 						duration = 0;
 					}
 				});
 
 				// Collapse any expanded sections inside of this panel first before deactivating.
 				if ( ! active ) {
 					_.each( construct.sections(), function( section ) {
 						section.collapse( { duration: 0 } );
 					} );
 				}
 			}
 
 			if ( ! $.contains( document, headContainer.get( 0 ) ) ) {
 				// If the element is not in the DOM, then jQuery.fn.slideUp() does nothing.
 				// In this case, a hard toggle is required instead.
 				headContainer.toggle( active );
 				if ( args.completeCallback ) {
 					args.completeCallback();
 				}
 			} else if ( active ) {
 				headContainer.slideDown( duration, args.completeCallback );
 			} else {
 				if ( construct.expanded() ) {
 					construct.collapse({
 						duration: duration,
 						completeCallback: function() {
 							headContainer.slideUp( duration, args.completeCallback );
 						}
 					});
 				} else {
 					headContainer.slideUp( duration, args.completeCallback );
 				}
 			}
 		},
 
 		/**
 		 * @since 4.1.0
 		 *
 		 * @param {boolean} active
 		 * @param {Object}  [params]
 		 * @return {boolean} False if state already applied.
 		 */
 		_toggleActive: function ( active, params ) {
 			var self = this;
 			params = params || {};
 			if ( ( active && this.active.get() ) || ( ! active && ! this.active.get() ) ) {
 				params.unchanged = true;
 				self.onChangeActive( self.active.get(), params );
 				return false;
 			} else {
 				params.unchanged = false;
 				this.activeArgumentsQueue.push( params );
 				this.active.set( active );
 				return true;
 			}
 		},
 
 		/**
 		 * @param {Object} [params]
 		 * @return {boolean} False if already active.
 		 */
 		activate: function ( params ) {
 			return this._toggleActive( true, params );
 		},
 
 		/**
 		 * @param {Object} [params]
 		 * @return {boolean} False if already inactive.
 		 */
 		deactivate: function ( params ) {
 			return this._toggleActive( false, params );
 		},
 
 		/**
 		 * To override by subclass, update the container's UI to reflect the provided active state.
 		 * @abstract
 		 */
 		onChangeExpanded: function () {
 			throw new Error( 'Must override with subclass.' );
 		},
 
 		/**
 		 * Handle the toggle logic for expand/collapse.
 		 *
 		 * @param {boolean}  expanded - The new state to apply.
 		 * @param {Object}   [params] - Object containing options for expand/collapse.
 		 * @param {Function} [params.completeCallback] - Function to call when expansion/collapse is complete.
 		 * @return {boolean} False if state already applied or active state is false.
 		 */
 		_toggleExpanded: function( expanded, params ) {
 			var instance = this, previousCompleteCallback;
 			params = params || {};
 			previousCompleteCallback = params.completeCallback;
 
 			// Short-circuit expand() if the instance is not active.
 			if ( expanded && ! instance.active() ) {
 				return false;
 			}
 
 			api.state( 'paneVisible' ).set( true );
 			params.completeCallback = function() {
 				if ( previousCompleteCallback ) {
 					previousCompleteCallback.apply( instance, arguments );
 				}
 				if ( expanded ) {
 					instance.container.trigger( 'expanded' );
 				} else {
 					instance.container.trigger( 'collapsed' );
 				}
 			};
 			if ( ( expanded && instance.expanded.get() ) || ( ! expanded && ! instance.expanded.get() ) ) {
 				params.unchanged = true;
 				instance.onChangeExpanded( instance.expanded.get(), params );
 				return false;
 			} else {
 				params.unchanged = false;
 				instance.expandedArgumentsQueue.push( params );
 				instance.expanded.set( expanded );
 				return true;
 			}
 		},
 
 		/**
 		 * @param {Object} [params]
 		 * @return {boolean} False if already expanded or if inactive.
 		 */
 		expand: function ( params ) {
 			return this._toggleExpanded( true, params );
 		},
 
 		/**
 		 * @param {Object} [params]
 		 * @return {boolean} False if already collapsed.
 		 */
 		collapse: function ( params ) {
 			return this._toggleExpanded( false, params );
 		},
 
 		/**
 		 * Animate container state change if transitions are supported by the browser.
 		 *
 		 * @since 4.7.0
 		 * @private
 		 *
 		 * @param {function} completeCallback Function to be called after transition is completed.
 		 * @return {void}
 		 */
 		_animateChangeExpanded: function( completeCallback ) {
 			// Return if CSS transitions are not supported.
 			if ( ! normalizedTransitionendEventName ) {
 				if ( completeCallback ) {
 					completeCallback();
 				}
 				return;
 			}
 
 			var construct = this,
 				content = construct.contentContainer,
 				overlay = content.closest( '.wp-full-overlay' ),
 				elements, transitionEndCallback, transitionParentPane;
 
 			// Determine set of elements that are affected by the animation.
 			elements = overlay.add( content );
 
 			if ( ! construct.panel || '' === construct.panel() ) {
 				transitionParentPane = true;
 			} else if ( api.panel( construct.panel() ).contentContainer.hasClass( 'skip-transition' ) ) {
 				transitionParentPane = true;
 			} else {
 				transitionParentPane = false;
 			}
 			if ( transitionParentPane ) {
 				elements = elements.add( '#customize-info, .customize-pane-parent' );
 			}
 
 			// Handle `transitionEnd` event.
 			transitionEndCallback = function( e ) {
 				if ( 2 !== e.eventPhase || ! $( e.target ).is( content ) ) {
 					return;
 				}
 				content.off( normalizedTransitionendEventName, transitionEndCallback );
 				elements.removeClass( 'busy' );
 				if ( completeCallback ) {
 					completeCallback();
 				}
 			};
 			content.on( normalizedTransitionendEventName, transitionEndCallback );
 			elements.addClass( 'busy' );
 
 			// Prevent screen flicker when pane has been scrolled before expanding.
 			_.defer( function() {
 				var container = content.closest( '.wp-full-overlay-sidebar-content' ),
 					currentScrollTop = container.scrollTop(),
 					previousScrollTop = content.data( 'previous-scrollTop' ) || 0,
 					expanded = construct.expanded();
 
 				if ( expanded && 0 < currentScrollTop ) {
 					content.css( 'top', currentScrollTop + 'px' );
 					content.data( 'previous-scrollTop', currentScrollTop );
 				} else if ( ! expanded && 0 < currentScrollTop + previousScrollTop ) {
 					content.css( 'top', previousScrollTop - currentScrollTop + 'px' );
 					container.scrollTop( previousScrollTop );
 				}
 			} );
 		},
 
 		/*
 		 * is documented using @borrows in the constructor.
 		 */
 		focus: focus,
 
 		/**
 		 * Return the container html, generated from its JS template, if it exists.
 		 *
 		 * @since 4.3.0
 		 */
 		getContainer: function () {
 			var template,
 				container = this;
 
 			if ( 0 !== $( '#tmpl-' + container.templateSelector ).length ) {
 				template = wp.template( container.templateSelector );
 			} else {
 				template = wp.template( 'customize-' + container.containerType + '-default' );
 			}
 			if ( template && container.container ) {
 				return template( _.extend(
 					{ id: container.id },
 					container.params
 				) ).toString().trim();
 			}
 
 			return '<li></li>';
 		},
 
 		/**
 		 * Find content element which is displayed when the section is expanded.
 		 *
 		 * After a construct is initialized, the return value will be available via the `contentContainer` property.
 		 * By default the element will be related it to the parent container with `aria-owns` and detached.
 		 * Custom panels and sections (such as the `NewMenuSection`) that do not have a sliding pane should
 		 * just return the content element without needing to add the `aria-owns` element or detach it from
 		 * the container. Such non-sliding pane custom sections also need to override the `onChangeExpanded`
 		 * method to handle animating the panel/section into and out of view.
 		 *
 		 * @since 4.7.0
 		 * @access public
 		 *
 		 * @return {jQuery} Detached content element.
 		 */
 		getContent: function() {
 			var construct = this,
 				container = construct.container,
 				content = container.find( '.accordion-section-content, .control-panel-content' ).first(),
 				contentId = 'sub-' + container.attr( 'id' ),
 				ownedElements = contentId,
 				alreadyOwnedElements = container.attr( 'aria-owns' );
 
 			if ( alreadyOwnedElements ) {
 				ownedElements = ownedElements + ' ' + alreadyOwnedElements;
 			}
 			container.attr( 'aria-owns', ownedElements );
 
 			return content.detach().attr( {
 				'id': contentId,
 				'class': 'customize-pane-child ' + content.attr( 'class' ) + ' ' + container.attr( 'class' )
 			} );
 		}
 	});
 
 	api.Section = Container.extend(/** @lends wp.customize.Section.prototype */{
 		containerType: 'section',
 		containerParent: '#customize-theme-controls',
 		containerPaneParent: '.customize-pane-parent',
 		defaults: {
 			title: '',
 			description: '',
 			priority: 100,
 			type: 'default',
 			content: null,
 			active: true,
 			instanceNumber: null,
 			panel: null,
 			customizeAction: ''
 		},
 
 		/**
 		 * @constructs wp.customize.Section
 		 * @augments   wp.customize~Container
 		 *
 		 * @since 4.1.0
 		 *
 		 * @param {string}  id - The ID for the section.
 		 * @param {Object}  options - Options.
 		 * @param {string}  options.title - Title shown when section is collapsed and expanded.
 		 * @param {string}  [options.description] - Description shown at the top of the section.
 		 * @param {number}  [options.priority=100] - The sort priority for the section.
 		 * @param {string}  [options.type=default] - The type of the section. See wp.customize.sectionConstructor.
 		 * @param {string}  [options.content] - The markup to be used for the section container. If empty, a JS template is used.
 		 * @param {boolean} [options.active=true] - Whether the section is active or not.
 		 * @param {string}  options.panel - The ID for the panel this section is associated with.
 		 * @param {string}  [options.customizeAction] - Additional context information shown before the section title when expanded.
 		 * @param {Object}  [options.params] - Deprecated wrapper for the above properties.
 		 */
 		initialize: function ( id, options ) {
 			var section = this, params;
 			params = options.params || options;
 
 			// Look up the type if one was not supplied.
 			if ( ! params.type ) {
 				_.find( api.sectionConstructor, function( Constructor, type ) {
 					if ( Constructor === section.constructor ) {
 						params.type = type;
 						return true;
 					}
 					return false;
 				} );
 			}
 
 			Container.prototype.initialize.call( section, id, params );
 
 			section.id = id;
 			section.panel = new api.Value();
 			section.panel.bind( function ( id ) {
 				$( section.headContainer ).toggleClass( 'control-subsection', !! id );
 			});
 			section.panel.set( section.params.panel || '' );
 			api.utils.bubbleChildValueChanges( section, [ 'panel' ] );
 
 			section.embed();
 			section.deferred.embedded.done( function () {
 				section.ready();
 			});
 		},
 
 		/**
 		 * Embed the container in the DOM when any parent panel is ready.
 		 *
 		 * @since 4.1.0
 		 */
 		embed: function () {
 			var inject,
 				section = this;
 
 			section.containerParent = api.ensure( section.containerParent );
 
 			// Watch for changes to the panel state.
 			inject = function ( panelId ) {
 				var parentContainer;
 				if ( panelId ) {
 					// The panel has been supplied, so wait until the panel object is registered.
 					api.panel( panelId, function ( panel ) {
 						// The panel has been registered, wait for it to become ready/initialized.
 						panel.deferred.embedded.done( function () {
 							parentContainer = panel.contentContainer;
 							if ( ! section.headContainer.parent().is( parentContainer ) ) {
 								parentContainer.append( section.headContainer );
 							}
 							if ( ! section.contentContainer.parent().is( section.headContainer ) ) {
 								section.containerParent.append( section.contentContainer );
 							}
 							section.deferred.embedded.resolve();
 						});
 					} );
 				} else {
 					// There is no panel, so embed the section in the root of the customizer.
 					parentContainer = api.ensure( section.containerPaneParent );
 					if ( ! section.headContainer.parent().is( parentContainer ) ) {
 						parentContainer.append( section.headContainer );
 					}
 					if ( ! section.contentContainer.parent().is( section.headContainer ) ) {
 						section.containerParent.append( section.contentContainer );
 					}
 					section.deferred.embedded.resolve();
 				}
 			};
 			section.panel.bind( inject );
 			inject( section.panel.get() ); // Since a section may never get a panel, assume that it won't ever get one.
 		},
 
 		/**
 		 * Add behaviors for the accordion section.
 		 *
 		 * @since 4.1.0
 		 */
 		attachEvents: function () {
 			var meta, content, section = this;
 
 			if ( section.container.hasClass( 'cannot-expand' ) ) {
 				return;
 			}
 
 			// Expand/Collapse accordion sections on click.
 			section.container.find( '.accordion-section-title, .customize-section-back' ).on( 'click keydown', function( event ) {
 				if ( api.utils.isKeydownButNotEnterEvent( event ) ) {
 					return;
 				}
 				event.preventDefault(); // Keep this AFTER the key filter above.
 
 				if ( section.expanded() ) {
 					section.collapse();
 				} else {
 					section.expand();
 				}
 			});
 
 			// This is very similar to what is found for api.Panel.attachEvents().
 			section.container.find( '.customize-section-title .customize-help-toggle' ).on( 'click', function() {
 
 				meta = section.container.find( '.section-meta' );
 				if ( meta.hasClass( 'cannot-expand' ) ) {
 					return;
 				}
 				content = meta.find( '.customize-section-description:first' );
 				content.toggleClass( 'open' );
 				content.slideToggle( section.defaultExpandedArguments.duration, function() {
 					content.trigger( 'toggled' );
 				} );
 				$( this ).attr( 'aria-expanded', function( i, attr ) {
 					return 'true' === attr ? 'false' : 'true';
 				});
 			});
 		},
 
 		/**
 		 * Return whether this section has any active controls.
 		 *
 		 * @since 4.1.0
 		 *
 		 * @return {boolean}
 		 */
 		isContextuallyActive: function () {
 			var section = this,
 				controls = section.controls(),
 				activeCount = 0;
 			_( controls ).each( function ( control ) {
 				if ( control.active() ) {
 					activeCount += 1;
 				}
 			} );
 			return ( activeCount !== 0 );
 		},
 
 		/**
 		 * Get the controls that are associated with this section, sorted by their priority Value.
 		 *
 		 * @since 4.1.0
 		 *
 		 * @return {Array}
 		 */
 		controls: function () {
 			return this._children( 'section', 'control' );
 		},
 
 		/**
 		 * Update UI to reflect expanded state.
 		 *
 		 * @since 4.1.0
 		 *
 		 * @param {boolean} expanded
 		 * @param {Object}  args
 		 */
 		onChangeExpanded: function ( expanded, args ) {
 			var section = this,
 				container = section.headContainer.closest( '.wp-full-overlay-sidebar-content' ),
 				content = section.contentContainer,
 				overlay = section.headContainer.closest( '.wp-full-overlay' ),
 				backBtn = content.find( '.customize-section-back' ),
 				sectionTitle = section.headContainer.find( '.accordion-section-title' ).first(),
 				expand, panel;
 
 			if ( expanded && ! content.hasClass( 'open' ) ) {
 
 				if ( args.unchanged ) {
 					expand = args.completeCallback;
 				} else {
 					expand = function() {
 						section._animateChangeExpanded( function() {
 							sectionTitle.attr( 'tabindex', '-1' );
 							backBtn.attr( 'tabindex', '0' );
 
 							backBtn.trigger( 'focus' );
 							content.css( 'top', '' );
 							container.scrollTop( 0 );
 
 							if ( args.completeCallback ) {
 								args.completeCallback();
 							}
 						} );
 
 						content.addClass( 'open' );
 						overlay.addClass( 'section-open' );
 						api.state( 'expandedSection' ).set( section );
 					}.bind( this );
 				}
 
 				if ( ! args.allowMultiple ) {
 					api.section.each( function ( otherSection ) {
 						if ( otherSection !== section ) {
 							otherSection.collapse( { duration: args.duration } );
 						}
 					});
 				}
 
 				if ( section.panel() ) {
 					api.panel( section.panel() ).expand({
 						duration: args.duration,
 						completeCallback: expand
 					});
 				} else {
 					if ( ! args.allowMultiple ) {
 						api.panel.each( function( panel ) {
 							panel.collapse();
 						});
 					}
 					expand();
 				}
 
 			} else if ( ! expanded && content.hasClass( 'open' ) ) {
 				if ( section.panel() ) {
 					panel = api.panel( section.panel() );
 					if ( panel.contentContainer.hasClass( 'skip-transition' ) ) {
 						panel.collapse();
 					}
 				}
 				section._animateChangeExpanded( function() {
 					backBtn.attr( 'tabindex', '-1' );
 					sectionTitle.attr( 'tabindex', '0' );
 
 					sectionTitle.trigger( 'focus' );
 					content.css( 'top', '' );
 
 					if ( args.completeCallback ) {
 						args.completeCallback();
 					}
 				} );
 
 				content.removeClass( 'open' );
 				overlay.removeClass( 'section-open' );
 				if ( section === api.state( 'expandedSection' ).get() ) {
 					api.state( 'expandedSection' ).set( false );
 				}
 
 			} else {
 				if ( args.completeCallback ) {
 					args.completeCallback();
 				}
 			}
 		}
 	});
 
 	api.ThemesSection = api.Section.extend(/** @lends wp.customize.ThemesSection.prototype */{
 		currentTheme: '',
 		overlay: '',
 		template: '',
 		screenshotQueue: null,
 		$window: null,
 		$body: null,
 		loaded: 0,
 		loading: false,
 		fullyLoaded: false,
 		term: '',
 		tags: '',
 		nextTerm: '',
 		nextTags: '',
 		filtersHeight: 0,
 		headerContainer: null,
 		updateCountDebounced: null,
 
 		/**
 		 * wp.customize.ThemesSection
 		 *
 		 * Custom section for themes that loads themes by category, and also
 		 * handles the theme-details view rendering and navigation.
 		 *
 		 * @constructs wp.customize.ThemesSection
 		 * @augments   wp.customize.Section
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {string} id - ID.
 		 * @param {Object} options - Options.
 		 * @return {void}
 		 */
 		initialize: function( id, options ) {
 			var section = this;
 			section.headerContainer = $();
 			section.$window = $( window );
 			section.$body = $( document.body );
 			api.Section.prototype.initialize.call( section, id, options );
 			section.updateCountDebounced = _.debounce( section.updateCount, 500 );
 		},
 
 		/**
 		 * Embed the section in the DOM when the themes panel is ready.
 		 *
 		 * Insert the section before the themes container. Assume that a themes section is within a panel, but not necessarily the themes panel.
 		 *
 		 * @since 4.9.0
 		 */
 		embed: function() {
 			var inject,
 				section = this;
 
 			// Watch for changes to the panel state.
 			inject = function( panelId ) {
 				var parentContainer;
 				api.panel( panelId, function( panel ) {
 
 					// The panel has been registered, wait for it to become ready/initialized.
 					panel.deferred.embedded.done( function() {
 						parentContainer = panel.contentContainer;
 						if ( ! section.headContainer.parent().is( parentContainer ) ) {
 							parentContainer.find( '.customize-themes-full-container-container' ).before( section.headContainer );
 						}
 						if ( ! section.contentContainer.parent().is( section.headContainer ) ) {
 							section.containerParent.append( section.contentContainer );
 						}
 						section.deferred.embedded.resolve();
 					});
 				} );
 			};
 			section.panel.bind( inject );
 			inject( section.panel.get() ); // Since a section may never get a panel, assume that it won't ever get one.
 		},
 
 		/**
 		 * Set up.
 		 *
 		 * @since 4.2.0
 		 *
 		 * @return {void}
 		 */
 		ready: function() {
 			var section = this;
 			section.overlay = section.container.find( '.theme-overlay' );
 			section.template = wp.template( 'customize-themes-details-view' );
 
 			// Bind global keyboard events.
 			section.container.on( 'keydown', function( event ) {
 				if ( ! section.overlay.find( '.theme-wrap' ).is( ':visible' ) ) {
 					return;
 				}
 
 				// Pressing the right arrow key fires a theme:next event.
 				if ( 39 === event.keyCode ) {
 					section.nextTheme();
 				}
 
 				// Pressing the left arrow key fires a theme:previous event.
 				if ( 37 === event.keyCode ) {
 					section.previousTheme();
 				}
 
 				// Pressing the escape key fires a theme:collapse event.
 				if ( 27 === event.keyCode ) {
 					if ( section.$body.hasClass( 'modal-open' ) ) {
 
 						// Escape from the details modal.
 						section.closeDetails();
 					} else {
 
 						// Escape from the inifinite scroll list.
 						section.headerContainer.find( '.customize-themes-section-title' ).focus();
 					}
 					event.stopPropagation(); // Prevent section from being collapsed.
 				}
 			});
 
 			section.renderScreenshots = _.throttle( section.renderScreenshots, 100 );
 
 			_.bindAll( section, 'renderScreenshots', 'loadMore', 'checkTerm', 'filtersChecked' );
 		},
 
 		/**
 		 * Override Section.isContextuallyActive method.
 		 *
 		 * Ignore the active states' of the contained theme controls, and just
 		 * use the section's own active state instead. This prevents empty search
 		 * results for theme sections from causing the section to become inactive.
 		 *
 		 * @since 4.2.0
 		 *
 		 * @return {boolean}
 		 */
 		isContextuallyActive: function () {
 			return this.active();
 		},
 
 		/**
 		 * Attach events.
 		 *
 		 * @since 4.2.0
 		 *
 		 * @return {void}
 		 */
 		attachEvents: function () {
 			var section = this, debounced;
 
 			// Expand/Collapse accordion sections on click.
 			section.container.find( '.customize-section-back' ).on( 'click keydown', function( event ) {
 				if ( api.utils.isKeydownButNotEnterEvent( event ) ) {
 					return;
 				}
 				event.preventDefault(); // Keep this AFTER the key filter above.
 				section.collapse();
 			});
 
 			section.headerContainer = $( '#accordion-section-' + section.id );
 
 			// Expand section/panel. Only collapse when opening another section.
 			section.headerContainer.on( 'click', '.customize-themes-section-title', function() {
 
 				// Toggle accordion filters under section headers.
 				if ( section.headerContainer.find( '.filter-details' ).length ) {
 					section.headerContainer.find( '.customize-themes-section-title' )
 						.toggleClass( 'details-open' )
 						.attr( 'aria-expanded', function( i, attr ) {
 							return 'true' === attr ? 'false' : 'true';
 						});
 					section.headerContainer.find( '.filter-details' ).slideToggle( 180 );
 				}
 
 				// Open the section.
 				if ( ! section.expanded() ) {
 					section.expand();
 				}
 			});
 
 			// Preview installed themes.
 			section.container.on( 'click', '.theme-actions .preview-theme', function() {
 				api.panel( 'themes' ).loadThemePreview( $( this ).data( 'slug' ) );
 			});
 
 			// Theme navigation in details view.
 			section.container.on( 'click', '.left', function() {
 				section.previousTheme();
 			});
 
 			section.container.on( 'click', '.right', function() {
 				section.nextTheme();
 			});
 
 			section.container.on( 'click', '.theme-backdrop, .close', function() {
 				section.closeDetails();
 			});
 
 			if ( 'local' === section.params.filter_type ) {
 
 				// Filter-search all theme objects loaded in the section.
 				section.container.on( 'input', '.wp-filter-search-themes', function( event ) {
 					section.filterSearch( event.currentTarget.value );
 				});
 
 			} else if ( 'remote' === section.params.filter_type ) {
 
 				// Event listeners for remote queries with user-entered terms.
 				// Search terms.
 				debounced = _.debounce( section.checkTerm, 500 ); // Wait until there is no input for 500 milliseconds to initiate a search.
 				section.contentContainer.on( 'input', '.wp-filter-search', function() {
 					if ( ! api.panel( 'themes' ).expanded() ) {
 						return;
 					}
 					debounced( section );
 					if ( ! section.expanded() ) {
 						section.expand();
 					}
 				});
 
 				// Feature filters.
 				section.contentContainer.on( 'click', '.filter-group input', function() {
 					section.filtersChecked();
 					section.checkTerm( section );
 				});
 			}
 
 			// Toggle feature filters.
 			section.contentContainer.on( 'click', '.feature-filter-toggle', function( e ) {
 				var $themeContainer = $( '.customize-themes-full-container' ),
 					$filterToggle = $( e.currentTarget );
 				section.filtersHeight = $filterToggle.parent().next( '.filter-drawer' ).height();
 
 				if ( 0 < $themeContainer.scrollTop() ) {
 					$themeContainer.animate( { scrollTop: 0 }, 400 );
 
 					if ( $filterToggle.hasClass( 'open' ) ) {
 						return;
 					}
 				}
 
 				$filterToggle
 					.toggleClass( 'open' )
 					.attr( 'aria-expanded', function( i, attr ) {
 						return 'true' === attr ? 'false' : 'true';
 					})
 					.parent().next( '.filter-drawer' ).slideToggle( 180, 'linear' );
 
 				if ( $filterToggle.hasClass( 'open' ) ) {
 					var marginOffset = 1018 < window.innerWidth ? 50 : 76;
 
 					section.contentContainer.find( '.themes' ).css( 'margin-top', section.filtersHeight + marginOffset );
 				} else {
 					section.contentContainer.find( '.themes' ).css( 'margin-top', 0 );
 				}
 			});
 
 			// Setup section cross-linking.
 			section.contentContainer.on( 'click', '.no-themes-local .search-dotorg-themes', function() {
 				api.section( 'wporg_themes' ).focus();
 			});
 
 			function updateSelectedState() {
 				var el = section.headerContainer.find( '.customize-themes-section-title' );
 				el.toggleClass( 'selected', section.expanded() );
 				el.attr( 'aria-expanded', section.expanded() ? 'true' : 'false' );
 				if ( ! section.expanded() ) {
 					el.removeClass( 'details-open' );
 				}
 			}
 			section.expanded.bind( updateSelectedState );
 			updateSelectedState();
 
 			// Move section controls to the themes area.
 			api.bind( 'ready', function () {
 				section.contentContainer = section.container.find( '.customize-themes-section' );
 				section.contentContainer.appendTo( $( '.customize-themes-full-container' ) );
 				section.container.add( section.headerContainer );
 			});
 		},
 
 		/**
 		 * Update UI to reflect expanded state
 		 *
 		 * @since 4.2.0
 		 *
 		 * @param {boolean}  expanded
 		 * @param {Object}   args
 		 * @param {boolean}  args.unchanged
 		 * @param {Function} args.completeCallback
 		 * @return {void}
 		 */
 		onChangeExpanded: function ( expanded, args ) {
 
 			// Note: there is a second argument 'args' passed.
 			var section = this,
 				container = section.contentContainer.closest( '.customize-themes-full-container' );
 
 			// Immediately call the complete callback if there were no changes.
 			if ( args.unchanged ) {
 				if ( args.completeCallback ) {
 					args.completeCallback();
 				}
 				return;
 			}
 
 			function expand() {
 
 				// Try to load controls if none are loaded yet.
 				if ( 0 === section.loaded ) {
 					section.loadThemes();
 				}
 
 				// Collapse any sibling sections/panels.
 				api.section.each( function ( otherSection ) {
 					var searchTerm;
 
 					if ( otherSection !== section ) {
 
 						// Try to sync the current search term to the new section.
 						if ( 'themes' === otherSection.params.type ) {
 							searchTerm = otherSection.contentContainer.find( '.wp-filter-search' ).val();
 							section.contentContainer.find( '.wp-filter-search' ).val( searchTerm );
 
 							// Directly initialize an empty remote search to avoid a race condition.
 							if ( '' === searchTerm && '' !== section.term && 'local' !== section.params.filter_type ) {
 								section.term = '';
 								section.initializeNewQuery( section.term, section.tags );
 							} else {
 								if ( 'remote' === section.params.filter_type ) {
 									section.checkTerm( section );
 								} else if ( 'local' === section.params.filter_type ) {
 									section.filterSearch( searchTerm );
 								}
 							}
 							otherSection.collapse( { duration: args.duration } );
 						}
 					}
 				});
 
 				section.contentContainer.addClass( 'current-section' );
 				container.scrollTop();
 
 				container.on( 'scroll', _.throttle( section.renderScreenshots, 300 ) );
 				container.on( 'scroll', _.throttle( section.loadMore, 300 ) );
 
 				if ( args.completeCallback ) {
 					args.completeCallback();
 				}
 				section.updateCount(); // Show this section's count.
 			}
 
 			if ( expanded ) {
 				if ( section.panel() && api.panel.has( section.panel() ) ) {
 					api.panel( section.panel() ).expand({
 						duration: args.duration,
 						completeCallback: expand
 					});
 				} else {
 					expand();
 				}
 			} else {
 				section.contentContainer.removeClass( 'current-section' );
 
 				// Always hide, even if they don't exist or are already hidden.
 				section.headerContainer.find( '.filter-details' ).slideUp( 180 );
 
 				container.off( 'scroll' );
 
 				if ( args.completeCallback ) {
 					args.completeCallback();
 				}
 			}
 		},
 
 		/**
 		 * Return the section's content element without detaching from the parent.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @return {jQuery}
 		 */
 		getContent: function() {
 			return this.container.find( '.control-section-content' );
 		},
 
 		/**
 		 * Load theme data via Ajax and add themes to the section as controls.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @return {void}
 		 */
 		loadThemes: function() {
 			var section = this, params, page, request;
 
 			if ( section.loading ) {
 				return; // We're already loading a batch of themes.
 			}
 
 			// Parameters for every API query. Additional params are set in PHP.
 			page = Math.ceil( section.loaded / 100 ) + 1;
 			params = {
 				'nonce': api.settings.nonce.switch_themes,
 				'wp_customize': 'on',
 				'theme_action': section.params.action,
 				'customized_theme': api.settings.theme.stylesheet,
 				'page': page
 			};
 
 			// Add fields for remote filtering.
 			if ( 'remote' === section.params.filter_type ) {
 				params.search = section.term;
 				params.tags = section.tags;
 			}
 
 			// Load themes.
 			section.headContainer.closest( '.wp-full-overlay' ).addClass( 'loading' );
 			section.loading = true;
 			section.container.find( '.no-themes' ).hide();
 			request = wp.ajax.post( 'customize_load_themes', params );
 			request.done(function( data ) {
 				var themes = data.themes;
 
 				// Stop and try again if the term changed while loading.
 				if ( '' !== section.nextTerm || '' !== section.nextTags ) {
 					if ( section.nextTerm ) {
 						section.term = section.nextTerm;
 					}
 					if ( section.nextTags ) {
 						section.tags = section.nextTags;
 					}
 					section.nextTerm = '';
 					section.nextTags = '';
 					section.loading = false;
 					section.loadThemes();
 					return;
 				}
 
 				if ( 0 !== themes.length ) {
 
 					section.loadControls( themes, page );
 
 					if ( 1 === page ) {
 
 						// Pre-load the first 3 theme screenshots.
 						_.each( section.controls().slice( 0, 3 ), function( control ) {
 							var img, src = control.params.theme.screenshot[0];
 							if ( src ) {
 								img = new Image();
 								img.src = src;
 							}
 						});
 						if ( 'local' !== section.params.filter_type ) {
 							wp.a11y.speak( api.settings.l10n.themeSearchResults.replace( '%d', data.info.results ) );
 						}
 					}
 
 					_.delay( section.renderScreenshots, 100 ); // Wait for the controls to become visible.
 
 					if ( 'local' === section.params.filter_type || 100 > themes.length ) {
 						// If we have less than the requested 100 themes, it's the end of the list.
 						section.fullyLoaded = true;
 					}
 				} else {
 					if ( 0 === section.loaded ) {
 						section.container.find( '.no-themes' ).show();
 						wp.a11y.speak( section.container.find( '.no-themes' ).text() );
 					} else {
 						section.fullyLoaded = true;
 					}
 				}
 				if ( 'local' === section.params.filter_type ) {
 					section.updateCount(); // Count of visible theme controls.
 				} else {
 					section.updateCount( data.info.results ); // Total number of results including pages not yet loaded.
 				}
 				section.container.find( '.unexpected-error' ).hide(); // Hide error notice in case it was previously shown.
 
 				// This cannot run on request.always, as section.loading may turn false before the new controls load in the success case.
 				section.headContainer.closest( '.wp-full-overlay' ).removeClass( 'loading' );
 				section.loading = false;
 			});
 			request.fail(function( data ) {
 				if ( 'undefined' === typeof data ) {
 					section.container.find( '.unexpected-error' ).show();
 					wp.a11y.speak( section.container.find( '.unexpected-error' ).text() );
 				} else if ( 'undefined' !== typeof console && console.error ) {
 					console.error( data );
 				}
 
 				// This cannot run on request.always, as section.loading may turn false before the new controls load in the success case.
 				section.headContainer.closest( '.wp-full-overlay' ).removeClass( 'loading' );
 				section.loading = false;
 			});
 		},
 
 		/**
 		 * Loads controls into the section from data received from loadThemes().
 		 *
 		 * @since 4.9.0
 		 * @param {Array}  themes - Array of theme data to create controls with.
 		 * @param {number} page   - Page of results being loaded.
 		 * @return {void}
 		 */
 		loadControls: function( themes, page ) {
 			var newThemeControls = [],
 				section = this;
 
 			// Add controls for each theme.
 			_.each( themes, function( theme ) {
 				var themeControl = new api.controlConstructor.theme( section.params.action + '_theme_' + theme.id, {
 					type: 'theme',
 					section: section.params.id,
 					theme: theme,
 					priority: section.loaded + 1
 				} );
 
 				api.control.add( themeControl );
 				newThemeControls.push( themeControl );
 				section.loaded = section.loaded + 1;
 			});
 
 			if ( 1 !== page ) {
 				Array.prototype.push.apply( section.screenshotQueue, newThemeControls ); // Add new themes to the screenshot queue.
 			}
 		},
 
 		/**
 		 * Determines whether more themes should be loaded, and loads them.
 		 *
 		 * @since 4.9.0
 		 * @return {void}
 		 */
 		loadMore: function() {
 			var section = this, container, bottom, threshold;
 			if ( ! section.fullyLoaded && ! section.loading ) {
 				container = section.container.closest( '.customize-themes-full-container' );
 
 				bottom = container.scrollTop() + container.height();
 				// Use a fixed distance to the bottom of loaded results to avoid unnecessarily
 				// loading results sooner when using a percentage of scroll distance.
 				threshold = container.prop( 'scrollHeight' ) - 3000;
 
 				if ( bottom > threshold ) {
 					section.loadThemes();
 				}
 			}
 		},
 
 		/**
 		 * Event handler for search input that filters visible controls.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {string} term - The raw search input value.
 		 * @return {void}
 		 */
 		filterSearch: function( term ) {
 			var count = 0,
 				visible = false,
 				section = this,
 				noFilter = ( api.section.has( 'wporg_themes' ) && 'remote' !== section.params.filter_type ) ? '.no-themes-local' : '.no-themes',
 				controls = section.controls(),
 				terms;
 
 			if ( section.loading ) {
 				return;
 			}
 
 			// Standardize search term format and split into an array of individual words.
 			terms = term.toLowerCase().trim().replace( /-/g, ' ' ).split( ' ' );
 
 			_.each( controls, function( control ) {
 				visible = control.filter( terms ); // Shows/hides and sorts control based on the applicability of the search term.
 				if ( visible ) {
 					count = count + 1;
 				}
 			});
 
 			if ( 0 === count ) {
 				section.container.find( noFilter ).show();
 				wp.a11y.speak( section.container.find( noFilter ).text() );
 			} else {
 				section.container.find( noFilter ).hide();
 			}
 
 			section.renderScreenshots();
 			api.reflowPaneContents();
 
 			// Update theme count.
 			section.updateCountDebounced( count );
 		},
 
 		/**
 		 * Event handler for search input that determines if the terms have changed and loads new controls as needed.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {wp.customize.ThemesSection} section - The current theme section, passed through the debouncer.
 		 * @return {void}
 		 */
 		checkTerm: function( section ) {
 			var newTerm;
 			if ( 'remote' === section.params.filter_type ) {
 				newTerm = section.contentContainer.find( '.wp-filter-search' ).val();
 				if ( section.term !== newTerm.trim() ) {
 					section.initializeNewQuery( newTerm, section.tags );
 				}
 			}
 		},
 
 		/**
 		 * Check for filters checked in the feature filter list and initialize a new query.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @return {void}
 		 */
 		filtersChecked: function() {
 			var section = this,
 			    items = section.container.find( '.filter-group' ).find( ':checkbox' ),
 			    tags = [];
 
 			_.each( items.filter( ':checked' ), function( item ) {
 				tags.push( $( item ).prop( 'value' ) );
 			});
 
 			// When no filters are checked, restore initial state. Update filter count.
 			if ( 0 === tags.length ) {
 				tags = '';
 				section.contentContainer.find( '.feature-filter-toggle .filter-count-0' ).show();
 				section.contentContainer.find( '.feature-filter-toggle .filter-count-filters' ).hide();
 			} else {
 				section.contentContainer.find( '.feature-filter-toggle .theme-filter-count' ).text( tags.length );
 				section.contentContainer.find( '.feature-filter-toggle .filter-count-0' ).hide();
 				section.contentContainer.find( '.feature-filter-toggle .filter-count-filters' ).show();
 			}
 
 			// Check whether tags have changed, and either load or queue them.
 			if ( ! _.isEqual( section.tags, tags ) ) {
 				if ( section.loading ) {
 					section.nextTags = tags;
 				} else {
 					if ( 'remote' === section.params.filter_type ) {
 						section.initializeNewQuery( section.term, tags );
 					} else if ( 'local' === section.params.filter_type ) {
 						section.filterSearch( tags.join( ' ' ) );
 					}
 				}
 			}
 		},
 
 		/**
 		 * Reset the current query and load new results.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {string} newTerm - New term.
 		 * @param {Array} newTags - New tags.
 		 * @return {void}
 		 */
 		initializeNewQuery: function( newTerm, newTags ) {
 			var section = this;
 
 			// Clear the controls in the section.
 			_.each( section.controls(), function( control ) {
 				control.container.remove();
 				api.control.remove( control.id );
 			});
 			section.loaded = 0;
 			section.fullyLoaded = false;
 			section.screenshotQueue = null;
 
 			// Run a new query, with loadThemes handling paging, etc.
 			if ( ! section.loading ) {
 				section.term = newTerm;
 				section.tags = newTags;
 				section.loadThemes();
 			} else {
 				section.nextTerm = newTerm; // This will reload from loadThemes() with the newest term once the current batch is loaded.
 				section.nextTags = newTags; // This will reload from loadThemes() with the newest tags once the current batch is loaded.
 			}
 			if ( ! section.expanded() ) {
 				section.expand(); // Expand the section if it isn't expanded.
 			}
 		},
 
 		/**
 		 * Render control's screenshot if the control comes into view.
 		 *
 		 * @since 4.2.0
 		 *
 		 * @return {void}
 		 */
 		renderScreenshots: function() {
 			var section = this;
 
 			// Fill queue initially, or check for more if empty.
 			if ( null === section.screenshotQueue || 0 === section.screenshotQueue.length ) {
 
 				// Add controls that haven't had their screenshots rendered.
 				section.screenshotQueue = _.filter( section.controls(), function( control ) {
 					return ! control.screenshotRendered;
 				});
 			}
 
 			// Are all screenshots rendered (for now)?
 			if ( ! section.screenshotQueue.length ) {
 				return;
 			}
 
 			section.screenshotQueue = _.filter( section.screenshotQueue, function( control ) {
 				var $imageWrapper = control.container.find( '.theme-screenshot' ),
 					$image = $imageWrapper.find( 'img' );
 
 				if ( ! $image.length ) {
 					return false;
 				}
 
 				if ( $image.is( ':hidden' ) ) {
 					return true;
 				}
 
 				// Based on unveil.js.
 				var wt = section.$window.scrollTop(),
 					wb = wt + section.$window.height(),
 					et = $image.offset().top,
 					ih = $imageWrapper.height(),
 					eb = et + ih,
 					threshold = ih * 3,
 					inView = eb >= wt - threshold && et <= wb + threshold;
 
 				if ( inView ) {
 					control.container.trigger( 'render-screenshot' );
 				}
 
 				// If the image is in view return false so it's cleared from the queue.
 				return ! inView;
 			} );
 		},
 
 		/**
 		 * Get visible count.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @return {number} Visible count.
 		 */
 		getVisibleCount: function() {
 			return this.contentContainer.find( 'li.customize-control:visible' ).length;
 		},
 
 		/**
 		 * Update the number of themes in the section.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @return {void}
 		 */
 		updateCount: function( count ) {
 			var section = this, countEl, displayed;
 
 			if ( ! count && 0 !== count ) {
 				count = section.getVisibleCount();
 			}
 
 			displayed = section.contentContainer.find( '.themes-displayed' );
 			countEl = section.contentContainer.find( '.theme-count' );
 
 			if ( 0 === count ) {
 				countEl.text( '0' );
 			} else {
 
 				// Animate the count change for emphasis.
 				displayed.fadeOut( 180, function() {
 					countEl.text( count );
 					displayed.fadeIn( 180 );
 				} );
 				wp.a11y.speak( api.settings.l10n.announceThemeCount.replace( '%d', count ) );
 			}
 		},
 
 		/**
 		 * Advance the modal to the next theme.
 		 *
 		 * @since 4.2.0
 		 *
 		 * @return {void}
 		 */
 		nextTheme: function () {
 			var section = this;
 			if ( section.getNextTheme() ) {
 				section.showDetails( section.getNextTheme(), function() {
 					section.overlay.find( '.right' ).focus();
 				} );
 			}
 		},
 
 		/**
 		 * Get the next theme model.
 		 *
 		 * @since 4.2.0
 		 *
 		 * @return {wp.customize.ThemeControl|boolean} Next theme.
 		 */
 		getNextTheme: function () {
 			var section = this, control, nextControl, sectionControls, i;
 			control = api.control( section.params.action + '_theme_' + section.currentTheme );
 			sectionControls = section.controls();
 			i = _.indexOf( sectionControls, control );
 			if ( -1 === i ) {
 				return false;
 			}
 
 			nextControl = sectionControls[ i + 1 ];
 			if ( ! nextControl ) {
 				return false;
 			}
 			return nextControl.params.theme;
 		},
 
 		/**
 		 * Advance the modal to the previous theme.
 		 *
 		 * @since 4.2.0
 		 * @return {void}
 		 */
 		previousTheme: function () {
 			var section = this;
 			if ( section.getPreviousTheme() ) {
 				section.showDetails( section.getPreviousTheme(), function() {
 					section.overlay.find( '.left' ).focus();
 				} );
 			}
 		},
 
 		/**
 		 * Get the previous theme model.
 		 *
 		 * @since 4.2.0
 		 * @return {wp.customize.ThemeControl|boolean} Previous theme.
 		 */
 		getPreviousTheme: function () {
 			var section = this, control, nextControl, sectionControls, i;
 			control = api.control( section.params.action + '_theme_' + section.currentTheme );
 			sectionControls = section.controls();
 			i = _.indexOf( sectionControls, control );
 			if ( -1 === i ) {
 				return false;
 			}
 
 			nextControl = sectionControls[ i - 1 ];
 			if ( ! nextControl ) {
 				return false;
 			}
 			return nextControl.params.theme;
 		},
 
 		/**
 		 * Disable buttons when we're viewing the first or last theme.
 		 *
 		 * @since 4.2.0
 		 *
 		 * @return {void}
 		 */
 		updateLimits: function () {
 			if ( ! this.getNextTheme() ) {
 				this.overlay.find( '.right' ).addClass( 'disabled' );
 			}
 			if ( ! this.getPreviousTheme() ) {
 				this.overlay.find( '.left' ).addClass( 'disabled' );
 			}
 		},
 
 		/**
 		 * Load theme preview.
 		 *
 		 * @since 4.7.0
 		 * @access public
 		 *
 		 * @deprecated
 		 * @param {string} themeId Theme ID.
 		 * @return {jQuery.promise} Promise.
 		 */
 		loadThemePreview: function( themeId ) {
 			return api.ThemesPanel.prototype.loadThemePreview.call( this, themeId );
 		},
 
 		/**
 		 * Render & show the theme details for a given theme model.
 		 *
 		 * @since 4.2.0
 		 *
 		 * @param {Object} theme - Theme.
 		 * @param {Function} [callback] - Callback once the details have been shown.
 		 * @return {void}
 		 */
 		showDetails: function ( theme, callback ) {
 			var section = this, panel = api.panel( 'themes' );
 			section.currentTheme = theme.id;
 			section.overlay.html( section.template( theme ) )
 				.fadeIn( 'fast' )
 				.focus();
 
 			function disableSwitchButtons() {
 				return ! panel.canSwitchTheme( theme.id );
 			}
 
 			// Temporary special function since supplying SFTP credentials does not work yet. See #42184.
 			function disableInstallButtons() {
 				return disableSwitchButtons() || false === api.settings.theme._canInstall || true === api.settings.theme._filesystemCredentialsNeeded;
 			}
 
 			section.overlay.find( 'button.preview, button.preview-theme' ).toggleClass( 'disabled', disableSwitchButtons() );
 			section.overlay.find( 'button.theme-install' ).toggleClass( 'disabled', disableInstallButtons() );
 
 			section.$body.addClass( 'modal-open' );
 			section.containFocus( section.overlay );
 			section.updateLimits();
 			wp.a11y.speak( api.settings.l10n.announceThemeDetails.replace( '%s', theme.name ) );
 			if ( callback ) {
 				callback();
 			}
 		},
 
 		/**
 		 * Close the theme details modal.
 		 *
 		 * @since 4.2.0
 		 *
 		 * @return {void}
 		 */
 		closeDetails: function () {
 			var section = this;
 			section.$body.removeClass( 'modal-open' );
 			section.overlay.fadeOut( 'fast' );
 			api.control( section.params.action + '_theme_' + section.currentTheme ).container.find( '.theme' ).focus();
 		},
 
 		/**
 		 * Keep tab focus within the theme details modal.
 		 *
 		 * @since 4.2.0
 		 *
 		 * @param {jQuery} el - Element to contain focus.
 		 * @return {void}
 		 */
 		containFocus: function( el ) {
 			var tabbables;
 
 			el.on( 'keydown', function( event ) {
 
 				// Return if it's not the tab key
 				// When navigating with prev/next focus is already handled.
 				if ( 9 !== event.keyCode ) {
 					return;
 				}
 
 				// Uses jQuery UI to get the tabbable elements.
 				tabbables = $( ':tabbable', el );
 
 				// Keep focus within the overlay.
 				if ( tabbables.last()[0] === event.target && ! event.shiftKey ) {
 					tabbables.first().focus();
 					return false;
 				} else if ( tabbables.first()[0] === event.target && event.shiftKey ) {
 					tabbables.last().focus();
 					return false;
 				}
 			});
 		}
 	});
 
 	api.OuterSection = api.Section.extend(/** @lends wp.customize.OuterSection.prototype */{
 
 		/**
 		 * Class wp.customize.OuterSection.
 		 *
 		 * Creates section outside of the sidebar, there is no ui to trigger collapse/expand so
 		 * it would require custom handling.
 		 *
 		 * @constructs wp.customize.OuterSection
 		 * @augments   wp.customize.Section
 		 *
 		 * @since 4.9.0
 		 *
 		 * @return {void}
 		 */
 		initialize: function() {
 			var section = this;
 			section.containerParent = '#customize-outer-theme-controls';
 			section.containerPaneParent = '.customize-outer-pane-parent';
 			api.Section.prototype.initialize.apply( section, arguments );
 		},
 
 		/**
 		 * Overrides api.Section.prototype.onChangeExpanded to prevent collapse/expand effect
 		 * on other sections and panels.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {boolean}  expanded - The expanded state to transition to.
 		 * @param {Object}   [args] - Args.
 		 * @param {boolean}  [args.unchanged] - Whether the state is already known to not be changed, and so short-circuit with calling completeCallback early.
 		 * @param {Function} [args.completeCallback] - Function to call when the slideUp/slideDown has completed.
 		 * @param {Object}   [args.duration] - The duration for the animation.
 		 */
 		onChangeExpanded: function( expanded, args ) {
 			var section = this,
 				container = section.headContainer.closest( '.wp-full-overlay-sidebar-content' ),
 				content = section.contentContainer,
 				backBtn = content.find( '.customize-section-back' ),
 				sectionTitle = section.headContainer.find( '.accordion-section-title' ).first(),
 				body = $( document.body ),
 				expand, panel;
 
 			body.toggleClass( 'outer-section-open', expanded );
 			section.container.toggleClass( 'open', expanded );
 			section.container.removeClass( 'busy' );
 			api.section.each( function( _section ) {
 				if ( 'outer' === _section.params.type && _section.id !== section.id ) {
 					_section.container.removeClass( 'open' );
 				}
 			} );
 
 			if ( expanded && ! content.hasClass( 'open' ) ) {
 
 				if ( args.unchanged ) {
 					expand = args.completeCallback;
 				} else {
 					expand = function() {
 						section._animateChangeExpanded( function() {
 							sectionTitle.attr( 'tabindex', '-1' );
 							backBtn.attr( 'tabindex', '0' );
 
 							backBtn.trigger( 'focus' );
 							content.css( 'top', '' );
 							container.scrollTop( 0 );
 
 							if ( args.completeCallback ) {
 								args.completeCallback();
 							}
 						} );
 
 						content.addClass( 'open' );
 					}.bind( this );
 				}
 
 				if ( section.panel() ) {
 					api.panel( section.panel() ).expand({
 						duration: args.duration,
 						completeCallback: expand
 					});
 				} else {
 					expand();
 				}
 
 			} else if ( ! expanded && content.hasClass( 'open' ) ) {
 				if ( section.panel() ) {
 					panel = api.panel( section.panel() );
 					if ( panel.contentContainer.hasClass( 'skip-transition' ) ) {
 						panel.collapse();
 					}
 				}
 				section._animateChangeExpanded( function() {
 					backBtn.attr( 'tabindex', '-1' );
 					sectionTitle.attr( 'tabindex', '0' );
 
 					sectionTitle.trigger( 'focus' );
 					content.css( 'top', '' );
 
 					if ( args.completeCallback ) {
 						args.completeCallback();
 					}
 				} );
 
 				content.removeClass( 'open' );
 
 			} else {
 				if ( args.completeCallback ) {
 					args.completeCallback();
 				}
 			}
 		}
 	});
 
 	api.Panel = Container.extend(/** @lends wp.customize.Panel.prototype */{
 		containerType: 'panel',
 
 		/**
 		 * @constructs wp.customize.Panel
 		 * @augments   wp.customize~Container
 		 *
 		 * @since 4.1.0
 		 *
 		 * @param {string}  id - The ID for the panel.
 		 * @param {Object}  options - Object containing one property: params.
 		 * @param {string}  options.title - Title shown when panel is collapsed and expanded.
 		 * @param {string}  [options.description] - Description shown at the top of the panel.
 		 * @param {number}  [options.priority=100] - The sort priority for the panel.
 		 * @param {string}  [options.type=default] - The type of the panel. See wp.customize.panelConstructor.
 		 * @param {string}  [options.content] - The markup to be used for the panel container. If empty, a JS template is used.
 		 * @param {boolean} [options.active=true] - Whether the panel is active or not.
 		 * @param {Object}  [options.params] - Deprecated wrapper for the above properties.
 		 */
 		initialize: function ( id, options ) {
 			var panel = this, params;
 			params = options.params || options;
 
 			// Look up the type if one was not supplied.
 			if ( ! params.type ) {
 				_.find( api.panelConstructor, function( Constructor, type ) {
 					if ( Constructor === panel.constructor ) {
 						params.type = type;
 						return true;
 					}
 					return false;
 				} );
 			}
 
 			Container.prototype.initialize.call( panel, id, params );
 
 			panel.embed();
 			panel.deferred.embedded.done( function () {
 				panel.ready();
 			});
 		},
 
 		/**
 		 * Embed the container in the DOM when any parent panel is ready.
 		 *
 		 * @since 4.1.0
 		 */
 		embed: function () {
 			var panel = this,
 				container = $( '#customize-theme-controls' ),
 				parentContainer = $( '.customize-pane-parent' ); // @todo This should be defined elsewhere, and to be configurable.
 
 			if ( ! panel.headContainer.parent().is( parentContainer ) ) {
 				parentContainer.append( panel.headContainer );
 			}
 			if ( ! panel.contentContainer.parent().is( panel.headContainer ) ) {
 				container.append( panel.contentContainer );
 			}
 			panel.renderContent();
 
 			panel.deferred.embedded.resolve();
 		},
 
 		/**
 		 * @since 4.1.0
 		 */
 		attachEvents: function () {
 			var meta, panel = this;
 
 			// Expand/Collapse accordion sections on click.
 			panel.headContainer.find( '.accordion-section-title' ).on( 'click keydown', function( event ) {
 				if ( api.utils.isKeydownButNotEnterEvent( event ) ) {
 					return;
 				}
 				event.preventDefault(); // Keep this AFTER the key filter above.
 
 				if ( ! panel.expanded() ) {
 					panel.expand();
 				}
 			});
 
 			// Close panel.
 			panel.container.find( '.customize-panel-back' ).on( 'click keydown', function( event ) {
 				if ( api.utils.isKeydownButNotEnterEvent( event ) ) {
 					return;
 				}
 				event.preventDefault(); // Keep this AFTER the key filter above.
 
 				if ( panel.expanded() ) {
 					panel.collapse();
 				}
 			});
 
 			meta = panel.container.find( '.panel-meta:first' );
 
 			meta.find( '> .accordion-section-title .customize-help-toggle' ).on( 'click', function() {
 				if ( meta.hasClass( 'cannot-expand' ) ) {
 					return;
 				}
 
 				var content = meta.find( '.customize-panel-description:first' );
 				if ( meta.hasClass( 'open' ) ) {
 					meta.toggleClass( 'open' );
 					content.slideUp( panel.defaultExpandedArguments.duration, function() {
 						content.trigger( 'toggled' );
 					} );
 					$( this ).attr( 'aria-expanded', false );
 				} else {
 					content.slideDown( panel.defaultExpandedArguments.duration, function() {
 						content.trigger( 'toggled' );
 					} );
 					meta.toggleClass( 'open' );
 					$( this ).attr( 'aria-expanded', true );
 				}
 			});
 
 		},
 
 		/**
 		 * Get the sections that are associated with this panel, sorted by their priority Value.
 		 *
 		 * @since 4.1.0
 		 *
 		 * @return {Array}
 		 */
 		sections: function () {
 			return this._children( 'panel', 'section' );
 		},
 
 		/**
 		 * Return whether this panel has any active sections.
 		 *
 		 * @since 4.1.0
 		 *
 		 * @return {boolean} Whether contextually active.
 		 */
 		isContextuallyActive: function () {
 			var panel = this,
 				sections = panel.sections(),
 				activeCount = 0;
 			_( sections ).each( function ( section ) {
 				if ( section.active() && section.isContextuallyActive() ) {
 					activeCount += 1;
 				}
 			} );
 			return ( activeCount !== 0 );
 		},
 
 		/**
 		 * Update UI to reflect expanded state.
 		 *
 		 * @since 4.1.0
 		 *
 		 * @param {boolean}  expanded
 		 * @param {Object}   args
 		 * @param {boolean}  args.unchanged
 		 * @param {Function} args.completeCallback
 		 * @return {void}
 		 */
 		onChangeExpanded: function ( expanded, args ) {
 
 			// Immediately call the complete callback if there were no changes.
 			if ( args.unchanged ) {
 				if ( args.completeCallback ) {
 					args.completeCallback();
 				}
 				return;
 			}
 
 			// Note: there is a second argument 'args' passed.
 			var panel = this,
 				accordionSection = panel.contentContainer,
 				overlay = accordionSection.closest( '.wp-full-overlay' ),
 				container = accordionSection.closest( '.wp-full-overlay-sidebar-content' ),
 				topPanel = panel.headContainer.find( '.accordion-section-title' ),
 				backBtn = accordionSection.find( '.customize-panel-back' ),
 				childSections = panel.sections(),
 				skipTransition;
 
 			if ( expanded && ! accordionSection.hasClass( 'current-panel' ) ) {
 				// Collapse any sibling sections/panels.
 				api.section.each( function ( section ) {
 					if ( panel.id !== section.panel() ) {
 						section.collapse( { duration: 0 } );
 					}
 				});
 				api.panel.each( function ( otherPanel ) {
 					if ( panel !== otherPanel ) {
 						otherPanel.collapse( { duration: 0 } );
 					}
 				});
 
 				if ( panel.params.autoExpandSoleSection && 1 === childSections.length && childSections[0].active.get() ) {
 					accordionSection.addClass( 'current-panel skip-transition' );
 					overlay.addClass( 'in-sub-panel' );
 
 					childSections[0].expand( {
 						completeCallback: args.completeCallback
 					} );
 				} else {
 					panel._animateChangeExpanded( function() {
 						topPanel.attr( 'tabindex', '-1' );
 						backBtn.attr( 'tabindex', '0' );
 
 						backBtn.trigger( 'focus' );
 						accordionSection.css( 'top', '' );
 						container.scrollTop( 0 );
 
 						if ( args.completeCallback ) {
 							args.completeCallback();
 						}
 					} );
 
 					accordionSection.addClass( 'current-panel' );
 					overlay.addClass( 'in-sub-panel' );
 				}
 
 				api.state( 'expandedPanel' ).set( panel );
 
 			} else if ( ! expanded && accordionSection.hasClass( 'current-panel' ) ) {
 				skipTransition = accordionSection.hasClass( 'skip-transition' );
 				if ( ! skipTransition ) {
 					panel._animateChangeExpanded( function() {
 						topPanel.attr( 'tabindex', '0' );
 						backBtn.attr( 'tabindex', '-1' );
 
 						topPanel.focus();
 						accordionSection.css( 'top', '' );
 
 						if ( args.completeCallback ) {
 							args.completeCallback();
 						}
 					} );
 				} else {
 					accordionSection.removeClass( 'skip-transition' );
 				}
 
 				overlay.removeClass( 'in-sub-panel' );
 				accordionSection.removeClass( 'current-panel' );
 				if ( panel === api.state( 'expandedPanel' ).get() ) {
 					api.state( 'expandedPanel' ).set( false );
 				}
 			}
 		},
 
 		/**
 		 * Render the panel from its JS template, if it exists.
 		 *
 		 * The panel's container must already exist in the DOM.
 		 *
 		 * @since 4.3.0
 		 */
 		renderContent: function () {
 			var template,
 				panel = this;
 
 			// Add the content to the container.
 			if ( 0 !== $( '#tmpl-' + panel.templateSelector + '-content' ).length ) {
 				template = wp.template( panel.templateSelector + '-content' );
 			} else {
 				template = wp.template( 'customize-panel-default-content' );
 			}
 			if ( template && panel.headContainer ) {
 				panel.contentContainer.html( template( _.extend(
 					{ id: panel.id },
 					panel.params
 				) ) );
 			}
 		}
 	});
 
 	api.ThemesPanel = api.Panel.extend(/** @lends wp.customize.ThemsPanel.prototype */{
 
 		/**
 		 *  Class wp.customize.ThemesPanel.
 		 *
 		 * Custom section for themes that displays without the customize preview.
 		 *
 		 * @constructs wp.customize.ThemesPanel
 		 * @augments   wp.customize.Panel
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {string} id - The ID for the panel.
 		 * @param {Object} options - Options.
 		 * @return {void}
 		 */
 		initialize: function( id, options ) {
 			var panel = this;
 			panel.installingThemes = [];
 			api.Panel.prototype.initialize.call( panel, id, options );
 		},
 
 		/**
 		 * Determine whether a given theme can be switched to, or in general.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {string} [slug] - Theme slug.
 		 * @return {boolean} Whether the theme can be switched to.
 		 */
 		canSwitchTheme: function canSwitchTheme( slug ) {
 			if ( slug && slug === api.settings.theme.stylesheet ) {
 				return true;
 			}
 			return 'publish' === api.state( 'selectedChangesetStatus' ).get() && ( '' === api.state( 'changesetStatus' ).get() || 'auto-draft' === api.state( 'changesetStatus' ).get() );
 		},
 
 		/**
 		 * Attach events.
 		 *
 		 * @since 4.9.0
 		 * @return {void}
 		 */
 		attachEvents: function() {
 			var panel = this;
 
 			// Attach regular panel events.
 			api.Panel.prototype.attachEvents.apply( panel );
 
 			// Temporary since supplying SFTP credentials does not work yet. See #42184.
 			if ( api.settings.theme._canInstall && api.settings.theme._filesystemCredentialsNeeded ) {
 				panel.notifications.add( new api.Notification( 'theme_install_unavailable', {
 					message: api.l10n.themeInstallUnavailable,
 					type: 'info',
 					dismissible: true
 				} ) );
 			}
 
 			function toggleDisabledNotifications() {
 				if ( panel.canSwitchTheme() ) {
 					panel.notifications.remove( 'theme_switch_unavailable' );
 				} else {
 					panel.notifications.add( new api.Notification( 'theme_switch_unavailable', {
 						message: api.l10n.themePreviewUnavailable,
 						type: 'warning'
 					} ) );
 				}
 			}
 			toggleDisabledNotifications();
 			api.state( 'selectedChangesetStatus' ).bind( toggleDisabledNotifications );
 			api.state( 'changesetStatus' ).bind( toggleDisabledNotifications );
 
 			// Collapse panel to customize the current theme.
 			panel.contentContainer.on( 'click', '.customize-theme', function() {
 				panel.collapse();
 			});
 
 			// Toggle between filtering and browsing themes on mobile.
 			panel.contentContainer.on( 'click', '.customize-themes-section-title, .customize-themes-mobile-back', function() {
 				$( '.wp-full-overlay' ).toggleClass( 'showing-themes' );
 			});
 
 			// Install (and maybe preview) a theme.
 			panel.contentContainer.on( 'click', '.theme-install', function( event ) {
 				panel.installTheme( event );
 			});
 
 			// Update a theme. Theme cards have the class, the details modal has the id.
 			panel.contentContainer.on( 'click', '.update-theme, #update-theme', function( event ) {
 
 				// #update-theme is a link.
 				event.preventDefault();
 				event.stopPropagation();
 
 				panel.updateTheme( event );
 			});
 
 			// Delete a theme.
 			panel.contentContainer.on( 'click', '.delete-theme', function( event ) {
 				panel.deleteTheme( event );
 			});
 
 			_.bindAll( panel, 'installTheme', 'updateTheme' );
 		},
 
 		/**
 		 * Update UI to reflect expanded state
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {boolean}  expanded - Expanded state.
 		 * @param {Object}   args - Args.
 		 * @param {boolean}  args.unchanged - Whether or not the state changed.
 		 * @param {Function} args.completeCallback - Callback to execute when the animation completes.
 		 * @return {void}
 		 */
 		onChangeExpanded: function( expanded, args ) {
 			var panel = this, overlay, sections, hasExpandedSection = false;
 
 			// Expand/collapse the panel normally.
 			api.Panel.prototype.onChangeExpanded.apply( this, [ expanded, args ] );
 
 			// Immediately call the complete callback if there were no changes.
 			if ( args.unchanged ) {
 				if ( args.completeCallback ) {
 					args.completeCallback();
 				}
 				return;
 			}
 
 			overlay = panel.headContainer.closest( '.wp-full-overlay' );
 
 			if ( expanded ) {
 				overlay
 					.addClass( 'in-themes-panel' )
 					.delay( 200 ).find( '.customize-themes-full-container' ).addClass( 'animate' );
 
 				_.delay( function() {
 					overlay.addClass( 'themes-panel-expanded' );
 				}, 200 );
 
 				// Automatically open the first section (except on small screens), if one isn't already expanded.
 				if ( 600 < window.innerWidth ) {
 					sections = panel.sections();
 					_.each( sections, function( section ) {
 						if ( section.expanded() ) {
 							hasExpandedSection = true;
 						}
 					} );
 					if ( ! hasExpandedSection && sections.length > 0 ) {
 						sections[0].expand();
 					}
 				}
 			} else {
 				overlay
 					.removeClass( 'in-themes-panel themes-panel-expanded' )
 					.find( '.customize-themes-full-container' ).removeClass( 'animate' );
 			}
 		},
 
 		/**
 		 * Install a theme via wp.updates.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {jQuery.Event} event - Event.
 		 * @return {jQuery.promise} Promise.
 		 */
 		installTheme: function( event ) {
 			var panel = this, preview, onInstallSuccess, slug = $( event.target ).data( 'slug' ), deferred = $.Deferred(), request;
 			preview = $( event.target ).hasClass( 'preview' );
 
 			// Temporary since supplying SFTP credentials does not work yet. See #42184.
 			if ( api.settings.theme._filesystemCredentialsNeeded ) {
 				deferred.reject({
 					errorCode: 'theme_install_unavailable'
 				});
 				return deferred.promise();
 			}
 
 			// Prevent loading a non-active theme preview when there is a drafted/scheduled changeset.
 			if ( ! panel.canSwitchTheme( slug ) ) {
 				deferred.reject({
 					errorCode: 'theme_switch_unavailable'
 				});
 				return deferred.promise();
 			}
 
 			// Theme is already being installed.
 			if ( _.contains( panel.installingThemes, slug ) ) {
 				deferred.reject({
 					errorCode: 'theme_already_installing'
 				});
 				return deferred.promise();
 			}
 
 			wp.updates.maybeRequestFilesystemCredentials( event );
 
 			onInstallSuccess = function( response ) {
 				var theme = false, themeControl;
 				if ( preview ) {
 					api.notifications.remove( 'theme_installing' );
 
 					panel.loadThemePreview( slug );
 
 				} else {
 					api.control.each( function( control ) {
 						if ( 'theme' === control.params.type && control.params.theme.id === response.slug ) {
 							theme = control.params.theme; // Used below to add theme control.
 							control.rerenderAsInstalled( true );
 						}
 					});
 
 					// Don't add the same theme more than once.
 					if ( ! theme || api.control.has( 'installed_theme_' + theme.id ) ) {
 						deferred.resolve( response );
 						return;
 					}
 
 					// Add theme control to installed section.
 					theme.type = 'installed';
 					themeControl = new api.controlConstructor.theme( 'installed_theme_' + theme.id, {
 						type: 'theme',
 						section: 'installed_themes',
 						theme: theme,
 						priority: 0 // Add all newly-installed themes to the top.
 					} );
 
 					api.control.add( themeControl );
 					api.control( themeControl.id ).container.trigger( 'render-screenshot' );
 
 					// Close the details modal if it's open to the installed theme.
 					api.section.each( function( section ) {
 						if ( 'themes' === section.params.type ) {
 							if ( theme.id === section.currentTheme ) { // Don't close the modal if the user has navigated elsewhere.
 								section.closeDetails();
 							}
 						}
 					});
 				}
 				deferred.resolve( response );
 			};
 
 			panel.installingThemes.push( slug ); // Note: we don't remove elements from installingThemes, since they shouldn't be installed again.
 			request = wp.updates.installTheme( {
 				slug: slug
 			} );
 
 			// Also preview the theme as the event is triggered on Install & Preview.
 			if ( preview ) {
 				api.notifications.add( new api.OverlayNotification( 'theme_installing', {
 					message: api.l10n.themeDownloading,
 					type: 'info',
 					loading: true
 				} ) );
 			}
 
 			request.done( onInstallSuccess );
 			request.fail( function() {
 				api.notifications.remove( 'theme_installing' );
 			} );
 
 			return deferred.promise();
 		},
 
 		/**
 		 * Load theme preview.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {string} themeId Theme ID.
 		 * @return {jQuery.promise} Promise.
 		 */
 		loadThemePreview: function( themeId ) {
 			var panel = this, deferred = $.Deferred(), onceProcessingComplete, urlParser, queryParams;
 
 			// Prevent loading a non-active theme preview when there is a drafted/scheduled changeset.
 			if ( ! panel.canSwitchTheme( themeId ) ) {
 				deferred.reject({
 					errorCode: 'theme_switch_unavailable'
 				});
 				return deferred.promise();
 			}
 
 			urlParser = document.createElement( 'a' );
 			urlParser.href = location.href;
 			queryParams = _.extend(
 				api.utils.parseQueryString( urlParser.search.substr( 1 ) ),
 				{
 					theme: themeId,
 					changeset_uuid: api.settings.changeset.uuid,
 					'return': api.settings.url['return']
 				}
 			);
 
 			// Include autosaved param to load autosave revision without prompting user to restore it.
 			if ( ! api.state( 'saved' ).get() ) {
 				queryParams.customize_autosaved = 'on';
 			}
 
 			urlParser.search = $.param( queryParams );
 
 			// Update loading message. Everything else is handled by reloading the page.
 			api.notifications.add( new api.OverlayNotification( 'theme_previewing', {
 				message: api.l10n.themePreviewWait,
 				type: 'info',
 				loading: true
 			} ) );
 
 			onceProcessingComplete = function() {
 				var request;
 				if ( api.state( 'processing' ).get() > 0 ) {
 					return;
 				}
 
 				api.state( 'processing' ).unbind( onceProcessingComplete );
 
 				request = api.requestChangesetUpdate( {}, { autosave: true } );
 				request.done( function() {
 					deferred.resolve();
 					$( window ).off( 'beforeunload.customize-confirm' );
 					location.replace( urlParser.href );
 				} );
 				request.fail( function() {
 
 					// @todo Show notification regarding failure.
 					api.notifications.remove( 'theme_previewing' );
 
 					deferred.reject();
 				} );
 			};
 
 			if ( 0 === api.state( 'processing' ).get() ) {
 				onceProcessingComplete();
 			} else {
 				api.state( 'processing' ).bind( onceProcessingComplete );
 			}
 
 			return deferred.promise();
 		},
 
 		/**
 		 * Update a theme via wp.updates.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {jQuery.Event} event - Event.
 		 * @return {void}
 		 */
 		updateTheme: function( event ) {
 			wp.updates.maybeRequestFilesystemCredentials( event );
 
 			$( document ).one( 'wp-theme-update-success', function( e, response ) {
 
 				// Rerender the control to reflect the update.
 				api.control.each( function( control ) {
 					if ( 'theme' === control.params.type && control.params.theme.id === response.slug ) {
 						control.params.theme.hasUpdate = false;
 						control.params.theme.version = response.newVersion;
 						setTimeout( function() {
 							control.rerenderAsInstalled( true );
 						}, 2000 );
 					}
 				});
 			} );
 
 			wp.updates.updateTheme( {
 				slug: $( event.target ).closest( '.notice' ).data( 'slug' )
 			} );
 		},
 
 		/**
 		 * Delete a theme via wp.updates.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {jQuery.Event} event - Event.
 		 * @return {void}
 		 */
 		deleteTheme: function( event ) {
 			var theme, section;
 			theme = $( event.target ).data( 'slug' );
 			section = api.section( 'installed_themes' );
 
 			event.preventDefault();
 
 			// Temporary since supplying SFTP credentials does not work yet. See #42184.
 			if ( api.settings.theme._filesystemCredentialsNeeded ) {
 				return;
 			}
 
 			// Confirmation dialog for deleting a theme.
 			if ( ! window.confirm( api.settings.l10n.confirmDeleteTheme ) ) {
 				return;
 			}
 
 			wp.updates.maybeRequestFilesystemCredentials( event );
 
 			$( document ).one( 'wp-theme-delete-success', function() {
 				var control = api.control( 'installed_theme_' + theme );
 
 				// Remove theme control.
 				control.container.remove();
 				api.control.remove( control.id );
 
 				// Update installed count.
 				section.loaded = section.loaded - 1;
 				section.updateCount();
 
 				// Rerender any other theme controls as uninstalled.
 				api.control.each( function( control ) {
 					if ( 'theme' === control.params.type && control.params.theme.id === theme ) {
 						control.rerenderAsInstalled( false );
 					}
 				});
 			} );
 
 			wp.updates.deleteTheme( {
 				slug: theme
 			} );
 
 			// Close modal and focus the section.
 			section.closeDetails();
 			section.focus();
 		}
 	});
 
 	api.Control = api.Class.extend(/** @lends wp.customize.Control.prototype */{
 		defaultActiveArguments: { duration: 'fast', completeCallback: $.noop },
 
 		/**
 		 * Default params.
 		 *
 		 * @since 4.9.0
 		 * @var {object}
 		 */
 		defaults: {
 			label: '',
 			description: '',
 			active: true,
 			priority: 10
 		},
 
 		/**
 		 * A Customizer Control.
 		 *
 		 * A control provides a UI element that allows a user to modify a Customizer Setting.
 		 *
 		 * @see PHP class WP_Customize_Control.
 		 *
 		 * @constructs wp.customize.Control
 		 * @augments   wp.customize.Class
 		 *
 		 * @borrows wp.customize~focus as this#focus
 		 * @borrows wp.customize~Container#activate as this#activate
 		 * @borrows wp.customize~Container#deactivate as this#deactivate
 		 * @borrows wp.customize~Container#_toggleActive as this#_toggleActive
 		 *
 		 * @param {string} id                       - Unique identifier for the control instance.
 		 * @param {Object} options                  - Options hash for the control instance.
 		 * @param {Object} options.type             - Type of control (e.g. text, radio, dropdown-pages, etc.)
 		 * @param {string} [options.content]        - The HTML content for the control or at least its container. This should normally be left blank and instead supplying a templateId.
 		 * @param {string} [options.templateId]     - Template ID for control's content.
 		 * @param {string} [options.priority=10]    - Order of priority to show the control within the section.
 		 * @param {string} [options.active=true]    - Whether the control is active.
 		 * @param {string} options.section          - The ID of the section the control belongs to.
 		 * @param {mixed}  [options.setting]        - The ID of the main setting or an instance of this setting.
 		 * @param {mixed}  options.settings         - An object with keys (e.g. default) that maps to setting IDs or Setting/Value objects, or an array of setting IDs or Setting/Value objects.
 		 * @param {mixed}  options.settings.default - The ID of the setting the control relates to.
 		 * @param {string} options.settings.data    - @todo Is this used?
 		 * @param {string} options.label            - Label.
 		 * @param {string} options.description      - Description.
 		 * @param {number} [options.instanceNumber] - Order in which this instance was created in relation to other instances.
 		 * @param {Object} [options.params]         - Deprecated wrapper for the above properties.
 		 * @return {void}
 		 */
 		initialize: function( id, options ) {
 			var control = this, deferredSettingIds = [], settings, gatherSettings;
 
 			control.params = _.extend(
 				{},
 				control.defaults,
 				control.params || {}, // In case subclass already defines.
 				options.params || options || {} // The options.params property is deprecated, but it is checked first for back-compat.
 			);
 
 			if ( ! api.Control.instanceCounter ) {
 				api.Control.instanceCounter = 0;
 			}
 			api.Control.instanceCounter++;
 			if ( ! control.params.instanceNumber ) {
 				control.params.instanceNumber = api.Control.instanceCounter;
 			}
 
 			// Look up the type if one was not supplied.
 			if ( ! control.params.type ) {
 				_.find( api.controlConstructor, function( Constructor, type ) {
 					if ( Constructor === control.constructor ) {
 						control.params.type = type;
 						return true;
 					}
 					return false;
 				} );
 			}
 
 			if ( ! control.params.content ) {
 				control.params.content = $( '<li></li>', {
 					id: 'customize-control-' + id.replace( /]/g, '' ).replace( /\[/g, '-' ),
 					'class': 'customize-control customize-control-' + control.params.type
 				} );
 			}
 
 			control.id = id;
 			control.selector = '#customize-control-' + id.replace( /\]/g, '' ).replace( /\[/g, '-' ); // Deprecated, likely dead code from time before #28709.
 			if ( control.params.content ) {
 				control.container = $( control.params.content );
 			} else {
 				control.container = $( control.selector ); // Likely dead, per above. See #28709.
 			}
 
 			if ( control.params.templateId ) {
 				control.templateSelector = control.params.templateId;
 			} else {
 				control.templateSelector = 'customize-control-' + control.params.type + '-content';
 			}
 
 			control.deferred = _.extend( control.deferred || {}, {
 				embedded: new $.Deferred()
 			} );
 			control.section = new api.Value();
 			control.priority = new api.Value();
 			control.active = new api.Value();
 			control.activeArgumentsQueue = [];
 			control.notifications = new api.Notifications({
 				alt: control.altNotice
 			});
 
 			control.elements = [];
 
 			control.active.bind( function ( active ) {
 				var args = control.activeArgumentsQueue.shift();
 				args = $.extend( {}, control.defaultActiveArguments, args );
 				control.onChangeActive( active, args );
 			} );
 
 			control.section.set( control.params.section );
 			control.priority.set( isNaN( control.params.priority ) ? 10 : control.params.priority );
 			control.active.set( control.params.active );
 
 			api.utils.bubbleChildValueChanges( control, [ 'section', 'priority', 'active' ] );
 
 			control.settings = {};
 
 			settings = {};
 			if ( control.params.setting ) {
 				settings['default'] = control.params.setting;
 			}
 			_.extend( settings, control.params.settings );
 
 			// Note: Settings can be an array or an object, with values being either setting IDs or Setting (or Value) objects.
 			_.each( settings, function( value, key ) {
 				var setting;
 				if ( _.isObject( value ) && _.isFunction( value.extended ) && value.extended( api.Value ) ) {
 					control.settings[ key ] = value;
 				} else if ( _.isString( value ) ) {
 					setting = api( value );
 					if ( setting ) {
 						control.settings[ key ] = setting;
 					} else {
 						deferredSettingIds.push( value );
 					}
 				}
 			} );
 
 			gatherSettings = function() {
 
 				// Fill-in all resolved settings.
 				_.each( settings, function ( settingId, key ) {
 					if ( ! control.settings[ key ] && _.isString( settingId ) ) {
 						control.settings[ key ] = api( settingId );
 					}
 				} );
 
 				// Make sure settings passed as array gets associated with default.
 				if ( control.settings[0] && ! control.settings['default'] ) {
 					control.settings['default'] = control.settings[0];
 				}
 
 				// Identify the main setting.
 				control.setting = control.settings['default'] || null;
 
 				control.linkElements(); // Link initial elements present in server-rendered content.
 				control.embed();
 			};
 
 			if ( 0 === deferredSettingIds.length ) {
 				gatherSettings();
 			} else {
 				api.apply( api, deferredSettingIds.concat( gatherSettings ) );
 			}
 
 			// After the control is embedded on the page, invoke the "ready" method.
 			control.deferred.embedded.done( function () {
 				control.linkElements(); // Link any additional elements after template is rendered by renderContent().
 				control.setupNotifications();
 				control.ready();
 			});
 		},
 
 		/**
 		 * Link elements between settings and inputs.
 		 *
 		 * @since 4.7.0
 		 * @access public
 		 *
 		 * @return {void}
 		 */
 		linkElements: function () {
 			var control = this, nodes, radios, element;
 
 			nodes = control.container.find( '[data-customize-setting-link], [data-customize-setting-key-link]' );
 			radios = {};
 
 			nodes.each( function () {
 				var node = $( this ), name, setting;
 
 				if ( node.data( 'customizeSettingLinked' ) ) {
 					return;
 				}
 				node.data( 'customizeSettingLinked', true ); // Prevent re-linking element.
 
 				if ( node.is( ':radio' ) ) {
 					name = node.prop( 'name' );
 					if ( radios[name] ) {
 						return;
 					}
 
 					radios[name] = true;
 					node = nodes.filter( '[name="' + name + '"]' );
 				}
 
 				// Let link by default refer to setting ID. If it doesn't exist, fallback to looking up by setting key.
 				if ( node.data( 'customizeSettingLink' ) ) {
 					setting = api( node.data( 'customizeSettingLink' ) );
 				} else if ( node.data( 'customizeSettingKeyLink' ) ) {
 					setting = control.settings[ node.data( 'customizeSettingKeyLink' ) ];
 				}
 
 				if ( setting ) {
 					element = new api.Element( node );
 					control.elements.push( element );
 					element.sync( setting );
 					element.set( setting() );
 				}
 			} );
 		},
 
 		/**
 		 * Embed the control into the page.
 		 */
 		embed: function () {
 			var control = this,
 				inject;
 
 			// Watch for changes to the section state.
 			inject = function ( sectionId ) {
 				var parentContainer;
 				if ( ! sectionId ) { // @todo Allow a control to be embedded without a section, for instance a control embedded in the front end.
 					return;
 				}
 				// Wait for the section to be registered.
 				api.section( sectionId, function ( section ) {
 					// Wait for the section to be ready/initialized.
 					section.deferred.embedded.done( function () {
 						parentContainer = ( section.contentContainer.is( 'ul' ) ) ? section.contentContainer : section.contentContainer.find( 'ul:first' );
 						if ( ! control.container.parent().is( parentContainer ) ) {
 							parentContainer.append( control.container );
 						}
 						control.renderContent();
 						control.deferred.embedded.resolve();
 					});
 				});
 			};
 			control.section.bind( inject );
 			inject( control.section.get() );
 		},
 
 		/**
 		 * Triggered when the control's markup has been injected into the DOM.
 		 *
 		 * @return {void}
 		 */
 		ready: function() {
 			var control = this, newItem;
 			if ( 'dropdown-pages' === control.params.type && control.params.allow_addition ) {
 				newItem = control.container.find( '.new-content-item' );
 				newItem.hide(); // Hide in JS to preserve flex display when showing.
 				control.container.on( 'click', '.add-new-toggle', function( e ) {
 					$( e.currentTarget ).slideUp( 180 );
 					newItem.slideDown( 180 );
 					newItem.find( '.create-item-input' ).focus();
 				});
 				control.container.on( 'click', '.add-content', function() {
 					control.addNewPage();
 				});
 				control.container.on( 'keydown', '.create-item-input', function( e ) {
 					if ( 13 === e.which ) { // Enter.
 						control.addNewPage();
 					}
 				});
 			}
 		},
 
 		/**
 		 * Get the element inside of a control's container that contains the validation error message.
 		 *
 		 * Control subclasses may override this to return the proper container to render notifications into.
 		 * Injects the notification container for existing controls that lack the necessary container,
 		 * including special handling for nav menu items and widgets.
 		 *
 		 * @since 4.6.0
 		 * @return {jQuery} Setting validation message element.
 		 */
 		getNotificationsContainerElement: function() {
 			var control = this, controlTitle, notificationsContainer;
 
 			notificationsContainer = control.container.find( '.customize-control-notifications-container:first' );
 			if ( notificationsContainer.length ) {
 				return notificationsContainer;
 			}
 
 			notificationsContainer = $( '<div class="customize-control-notifications-container"></div>' );
 
 			if ( control.container.hasClass( 'customize-control-nav_menu_item' ) ) {
 				control.container.find( '.menu-item-settings:first' ).prepend( notificationsContainer );
 			} else if ( control.container.hasClass( 'customize-control-widget_form' ) ) {
 				control.container.find( '.widget-inside:first' ).prepend( notificationsContainer );
 			} else {
 				controlTitle = control.container.find( '.customize-control-title' );
 				if ( controlTitle.length ) {
 					controlTitle.after( notificationsContainer );
 				} else {
 					control.container.prepend( notificationsContainer );
 				}
 			}
 			return notificationsContainer;
 		},
 
 		/**
 		 * Set up notifications.
 		 *
 		 * @since 4.9.0
 		 * @return {void}
 		 */
 		setupNotifications: function() {
 			var control = this, renderNotificationsIfVisible, onSectionAssigned;
 
 			// Add setting notifications to the control notification.
 			_.each( control.settings, function( setting ) {
 				if ( ! setting.notifications ) {
 					return;
 				}
 				setting.notifications.bind( 'add', function( settingNotification ) {
 					var params = _.extend(
 						{},
 						settingNotification,
 						{
 							setting: setting.id
 						}
 					);
 					control.notifications.add( new api.Notification( setting.id + ':' + settingNotification.code, params ) );
 				} );
 				setting.notifications.bind( 'remove', function( settingNotification ) {
 					control.notifications.remove( setting.id + ':' + settingNotification.code );
 				} );
 			} );
 
 			renderNotificationsIfVisible = function() {
 				var sectionId = control.section();
 				if ( ! sectionId || ( api.section.has( sectionId ) && api.section( sectionId ).expanded() ) ) {
 					control.notifications.render();
 				}
 			};
 
 			control.notifications.bind( 'rendered', function() {
 				var notifications = control.notifications.get();
 				control.container.toggleClass( 'has-notifications', 0 !== notifications.length );
 				control.container.toggleClass( 'has-error', 0 !== _.where( notifications, { type: 'error' } ).length );
 			} );
 
 			onSectionAssigned = function( newSectionId, oldSectionId ) {
 				if ( oldSectionId && api.section.has( oldSectionId ) ) {
 					api.section( oldSectionId ).expanded.unbind( renderNotificationsIfVisible );
 				}
 				if ( newSectionId ) {
 					api.section( newSectionId, function( section ) {
 						section.expanded.bind( renderNotificationsIfVisible );
 						renderNotificationsIfVisible();
 					});
 				}
 			};
 
 			control.section.bind( onSectionAssigned );
 			onSectionAssigned( control.section.get() );
 			control.notifications.bind( 'change', _.debounce( renderNotificationsIfVisible ) );
 		},
 
 		/**
 		 * Render notifications.
 		 *
 		 * Renders the `control.notifications` into the control's container.
 		 * Control subclasses may override this method to do their own handling
 		 * of rendering notifications.
 		 *
 		 * @deprecated in favor of `control.notifications.render()`
 		 * @since 4.6.0
 		 * @this {wp.customize.Control}
 		 */
 		renderNotifications: function() {
 			var control = this, container, notifications, hasError = false;
 
 			if ( 'undefined' !== typeof console && console.warn ) {
 				console.warn( '[DEPRECATED] wp.customize.Control.prototype.renderNotifications() is deprecated in favor of instantating a wp.customize.Notifications and calling its render() method.' );
 			}
 
 			container = control.getNotificationsContainerElement();
 			if ( ! container || ! container.length ) {
 				return;
 			}
 			notifications = [];
 			control.notifications.each( function( notification ) {
 				notifications.push( notification );
 				if ( 'error' === notification.type ) {
 					hasError = true;
 				}
 			} );
 
 			if ( 0 === notifications.length ) {
 				container.stop().slideUp( 'fast' );
 			} else {
 				container.stop().slideDown( 'fast', null, function() {
 					$( this ).css( 'height', 'auto' );
 				} );
 			}
 
 			if ( ! control.notificationsTemplate ) {
 				control.notificationsTemplate = wp.template( 'customize-control-notifications' );
 			}
 
 			control.container.toggleClass( 'has-notifications', 0 !== notifications.length );
 			control.container.toggleClass( 'has-error', hasError );
 			container.empty().append(
 				control.notificationsTemplate( { notifications: notifications, altNotice: Boolean( control.altNotice ) } ).trim()
 			);
 		},
 
 		/**
 		 * Normal controls do not expand, so just expand its parent
 		 *
 		 * @param {Object} [params]
 		 */
 		expand: function ( params ) {
 			api.section( this.section() ).expand( params );
 		},
 
 		/*
 		 * Documented using @borrows in the constructor.
 		 */
 		focus: focus,
 
 		/**
 		 * Update UI in response to a change in the control's active state.
 		 * This does not change the active state, it merely handles the behavior
 		 * for when it does change.
 		 *
 		 * @since 4.1.0
 		 *
 		 * @param {boolean}  active
 		 * @param {Object}   args
 		 * @param {number}   args.duration
 		 * @param {Function} args.completeCallback
 		 */
 		onChangeActive: function ( active, args ) {
 			if ( args.unchanged ) {
 				if ( args.completeCallback ) {
 					args.completeCallback();
 				}
 				return;
 			}
 
 			if ( ! $.contains( document, this.container[0] ) ) {
 				// jQuery.fn.slideUp is not hiding an element if it is not in the DOM.
 				this.container.toggle( active );
 				if ( args.completeCallback ) {
 					args.completeCallback();
 				}
 			} else if ( active ) {
 				this.container.slideDown( args.duration, args.completeCallback );
 			} else {
 				this.container.slideUp( args.duration, args.completeCallback );
 			}
 		},
 
 		/**
 		 * @deprecated 4.1.0 Use this.onChangeActive() instead.
 		 */
 		toggle: function ( active ) {
 			return this.onChangeActive( active, this.defaultActiveArguments );
 		},
 
 		/*
 		 * Documented using @borrows in the constructor
 		 */
 		activate: Container.prototype.activate,
 
 		/*
 		 * Documented using @borrows in the constructor
 		 */
 		deactivate: Container.prototype.deactivate,
 
 		/*
 		 * Documented using @borrows in the constructor
 		 */
 		_toggleActive: Container.prototype._toggleActive,
 
 		// @todo This function appears to be dead code and can be removed.
 		dropdownInit: function() {
 			var control      = this,
 				statuses     = this.container.find('.dropdown-status'),
 				params       = this.params,
 				toggleFreeze = false,
 				update       = function( to ) {
 					if ( 'string' === typeof to && params.statuses && params.statuses[ to ] ) {
 						statuses.html( params.statuses[ to ] ).show();
 					} else {
 						statuses.hide();
 					}
 				};
 
 			// Support the .dropdown class to open/close complex elements.
 			this.container.on( 'click keydown', '.dropdown', function( event ) {
 				if ( api.utils.isKeydownButNotEnterEvent( event ) ) {
 					return;
 				}
 
 				event.preventDefault();
 
 				if ( ! toggleFreeze ) {
 					control.container.toggleClass( 'open' );
 				}
 
 				if ( control.container.hasClass( 'open' ) ) {
 					control.container.parent().parent().find( 'li.library-selected' ).focus();
 				}
 
 				// Don't want to fire focus and click at same time.
 				toggleFreeze = true;
 				setTimeout(function () {
 					toggleFreeze = false;
 				}, 400);
 			});
 
 			this.setting.bind( update );
 			update( this.setting() );
 		},
 
 		/**
 		 * Render the control from its JS template, if it exists.
 		 *
 		 * The control's container must already exist in the DOM.
 		 *
 		 * @since 4.1.0
 		 */
 		renderContent: function () {
 			var control = this, template, standardTypes, templateId, sectionId;
 
 			standardTypes = [
 				'button',
 				'checkbox',
 				'date',
 				'datetime-local',
 				'email',
 				'month',
 				'number',
 				'password',
 				'radio',
 				'range',
 				'search',
 				'select',
 				'tel',
 				'time',
 				'text',
 				'textarea',
 				'week',
 				'url'
 			];
 
 			templateId = control.templateSelector;
 
 			// Use default content template when a standard HTML type is used,
 			// there isn't a more specific template existing, and the control container is empty.
 			if ( templateId === 'customize-control-' + control.params.type + '-content' &&
 				_.contains( standardTypes, control.params.type ) &&
 				! document.getElementById( 'tmpl-' + templateId ) &&
 				0 === control.container.children().length )
 			{
 				templateId = 'customize-control-default-content';
 			}
 
 			// Replace the container element's content with the control.
 			if ( document.getElementById( 'tmpl-' + templateId ) ) {
 				template = wp.template( templateId );
 				if ( template && control.container ) {
 					control.container.html( template( control.params ) );
 				}
 			}
 
 			// Re-render notifications after content has been re-rendered.
 			control.notifications.container = control.getNotificationsContainerElement();
 			sectionId = control.section();
 			if ( ! sectionId || ( api.section.has( sectionId ) && api.section( sectionId ).expanded() ) ) {
 				control.notifications.render();
 			}
 		},
 
 		/**
 		 * Add a new page to a dropdown-pages control reusing menus code for this.
 		 *
 		 * @since 4.7.0
 		 * @access private
 		 *
 		 * @return {void}
 		 */
 		addNewPage: function () {
 			var control = this, promise, toggle, container, input, title, select;
 
 			if ( 'dropdown-pages' !== control.params.type || ! control.params.allow_addition || ! api.Menus ) {
 				return;
 			}
 
 			toggle = control.container.find( '.add-new-toggle' );
 			container = control.container.find( '.new-content-item' );
 			input = control.container.find( '.create-item-input' );
 			title = input.val();
 			select = control.container.find( 'select' );
 
 			if ( ! title ) {
 				input.addClass( 'invalid' );
 				return;
 			}
 
 			input.removeClass( 'invalid' );
 			input.attr( 'disabled', 'disabled' );
 
 			// The menus functions add the page, publish when appropriate,
 			// and also add the new page to the dropdown-pages controls.
 			promise = api.Menus.insertAutoDraftPost( {
 				post_title: title,
 				post_type: 'page'
 			} );
 			promise.done( function( data ) {
 				var availableItem, $content, itemTemplate;
 
 				// Prepare the new page as an available menu item.
 				// See api.Menus.submitNew().
 				availableItem = new api.Menus.AvailableItemModel( {
 					'id': 'post-' + data.post_id, // Used for available menu item Backbone models.
 					'title': title,
 					'type': 'post_type',
 					'type_label': api.Menus.data.l10n.page_label,
 					'object': 'page',
 					'object_id': data.post_id,
 					'url': data.url
 				} );
 
 				// Add the new item to the list of available menu items.
 				api.Menus.availableMenuItemsPanel.collection.add( availableItem );
 				$content = $( '#available-menu-items-post_type-page' ).find( '.available-menu-items-list' );
 				itemTemplate = wp.template( 'available-menu-item' );
 				$content.prepend( itemTemplate( availableItem.attributes ) );
 
 				// Focus the select control.
 				select.focus();
 				control.setting.set( String( data.post_id ) ); // Triggers a preview refresh and updates the setting.
 
 				// Reset the create page form.
 				container.slideUp( 180 );
 				toggle.slideDown( 180 );
 			} );
 			promise.always( function() {
 				input.val( '' ).removeAttr( 'disabled' );
 			} );
 		}
 	});
 
 	/**
 	 * A colorpicker control.
 	 *
 	 * @class    wp.customize.ColorControl
 	 * @augments wp.customize.Control
 	 */
 	api.ColorControl = api.Control.extend(/** @lends wp.customize.ColorControl.prototype */{
 		ready: function() {
 			var control = this,
 				isHueSlider = this.params.mode === 'hue',
 				updating = false,
 				picker;
 
 			if ( isHueSlider ) {
 				picker = this.container.find( '.color-picker-hue' );
 				picker.val( control.setting() ).wpColorPicker({
 					change: function( event, ui ) {
 						updating = true;
 						control.setting( ui.color.h() );
 						updating = false;
 					}
 				});
 			} else {
 				picker = this.container.find( '.color-picker-hex' );
 				picker.val( control.setting() ).wpColorPicker({
 					change: function() {
 						updating = true;
 						control.setting.set( picker.wpColorPicker( 'color' ) );
 						updating = false;
 					},
 					clear: function() {
 						updating = true;
 						control.setting.set( '' );
 						updating = false;
 					}
 				});
 			}
 
 			control.setting.bind( function ( value ) {
 				// Bail if the update came from the control itself.
 				if ( updating ) {
 					return;
 				}
 				picker.val( value );
 				picker.wpColorPicker( 'color', value );
 			} );
 
 			// Collapse color picker when hitting Esc instead of collapsing the current section.
 			control.container.on( 'keydown', function( event ) {
 				var pickerContainer;
 				if ( 27 !== event.which ) { // Esc.
 					return;
 				}
 				pickerContainer = control.container.find( '.wp-picker-container' );
 				if ( pickerContainer.hasClass( 'wp-picker-active' ) ) {
 					picker.wpColorPicker( 'close' );
 					control.container.find( '.wp-color-result' ).focus();
 					event.stopPropagation(); // Prevent section from being collapsed.
 				}
 			} );
 		}
 	});
 
 	/**
 	 * A control that implements the media modal.
 	 *
 	 * @class    wp.customize.MediaControl
 	 * @augments wp.customize.Control
 	 */
 	api.MediaControl = api.Control.extend(/** @lends wp.customize.MediaControl.prototype */{
 
 		/**
 		 * When the control's DOM structure is ready,
 		 * set up internal event bindings.
 		 */
 		ready: function() {
 			var control = this;
 			// Shortcut so that we don't have to use _.bind every time we add a callback.
 			_.bindAll( control, 'restoreDefault', 'removeFile', 'openFrame', 'select', 'pausePlayer' );
 
 			// Bind events, with delegation to facilitate re-rendering.
 			control.container.on( 'click keydown', '.upload-button', control.openFrame );
 			control.container.on( 'click keydown', '.upload-button', control.pausePlayer );
 			control.container.on( 'click keydown', '.thumbnail-image img', control.openFrame );
 			control.container.on( 'click keydown', '.default-button', control.restoreDefault );
 			control.container.on( 'click keydown', '.remove-button', control.pausePlayer );
 			control.container.on( 'click keydown', '.remove-button', control.removeFile );
 			control.container.on( 'click keydown', '.remove-button', control.cleanupPlayer );
 
 			// Resize the player controls when it becomes visible (ie when section is expanded).
 			api.section( control.section() ).container
 				.on( 'expanded', function() {
 					if ( control.player ) {
 						control.player.setControlsSize();
 					}
 				})
 				.on( 'collapsed', function() {
 					control.pausePlayer();
 				});
 
 			/**
 			 * Set attachment data and render content.
 			 *
 			 * Note that BackgroundImage.prototype.ready applies this ready method
 			 * to itself. Since BackgroundImage is an UploadControl, the value
 			 * is the attachment URL instead of the attachment ID. In this case
 			 * we skip fetching the attachment data because we have no ID available,
 			 * and it is the responsibility of the UploadControl to set the control's
 			 * attachmentData before calling the renderContent method.
 			 *
 			 * @param {number|string} value Attachment
 			 */
 			function setAttachmentDataAndRenderContent( value ) {
 				var hasAttachmentData = $.Deferred();
 
 				if ( control.extended( api.UploadControl ) ) {
 					hasAttachmentData.resolve();
 				} else {
 					value = parseInt( value, 10 );
 					if ( _.isNaN( value ) || value <= 0 ) {
 						delete control.params.attachment;
 						hasAttachmentData.resolve();
 					} else if ( control.params.attachment && control.params.attachment.id === value ) {
 						hasAttachmentData.resolve();
 					}
 				}
 
 				// Fetch the attachment data.
 				if ( 'pending' === hasAttachmentData.state() ) {
 					wp.media.attachment( value ).fetch().done( function() {
 						control.params.attachment = this.attributes;
 						hasAttachmentData.resolve();
 
 						// Send attachment information to the preview for possible use in `postMessage` transport.
 						wp.customize.previewer.send( control.setting.id + '-attachment-data', this.attributes );
 					} );
 				}
 
 				hasAttachmentData.done( function() {
 					control.renderContent();
 				} );
 			}
 
 			// Ensure attachment data is initially set (for dynamically-instantiated controls).
 			setAttachmentDataAndRenderContent( control.setting() );
 
 			// Update the attachment data and re-render the control when the setting changes.
 			control.setting.bind( setAttachmentDataAndRenderContent );
 		},
 
 		pausePlayer: function () {
 			this.player && this.player.pause();
 		},
 
 		cleanupPlayer: function () {
 			this.player && wp.media.mixin.removePlayer( this.player );
 		},
 
 		/**
 		 * Open the media modal.
 		 */
 		openFrame: function( event ) {
 			if ( api.utils.isKeydownButNotEnterEvent( event ) ) {
 				return;
 			}
 
 			event.preventDefault();
 
 			if ( ! this.frame ) {
 				this.initFrame();
 			}
 
 			this.frame.open();
 		},
 
 		/**
 		 * Create a media modal select frame, and store it so the instance can be reused when needed.
 		 */
 		initFrame: function() {
 			this.frame = wp.media({
 				button: {
 					text: this.params.button_labels.frame_button
 				},
 				states: [
 					new wp.media.controller.Library({
 						title:     this.params.button_labels.frame_title,
 						library:   wp.media.query({ type: this.params.mime_type }),
 						multiple:  false,
 						date:      false
 					})
 				]
 			});
 
 			// When a file is selected, run a callback.
 			this.frame.on( 'select', this.select );
 		},
 
 		/**
 		 * Callback handler for when an attachment is selected in the media modal.
 		 * Gets the selected image information, and sets it within the control.
 		 */
 		select: function() {
 			// Get the attachment from the modal frame.
 			var node,
 				attachment = this.frame.state().get( 'selection' ).first().toJSON(),
 				mejsSettings = window._wpmejsSettings || {};
 
 			this.params.attachment = attachment;
 
 			// Set the Customizer setting; the callback takes care of rendering.
 			this.setting( attachment.id );
 			node = this.container.find( 'audio, video' ).get(0);
 
 			// Initialize audio/video previews.
 			if ( node ) {
 				this.player = new MediaElementPlayer( node, mejsSettings );
 			} else {
 				this.cleanupPlayer();
 			}
 		},
 
 		/**
 		 * Reset the setting to the default value.
 		 */
 		restoreDefault: function( event ) {
 			if ( api.utils.isKeydownButNotEnterEvent( event ) ) {
 				return;
 			}
 			event.preventDefault();
 
 			this.params.attachment = this.params.defaultAttachment;
 			this.setting( this.params.defaultAttachment.url );
 		},
 
 		/**
 		 * Called when the "Remove" link is clicked. Empties the setting.
 		 *
 		 * @param {Object} event jQuery Event object
 		 */
 		removeFile: function( event ) {
 			if ( api.utils.isKeydownButNotEnterEvent( event ) ) {
 				return;
 			}
 			event.preventDefault();
 
 			this.params.attachment = {};
 			this.setting( '' );
 			this.renderContent(); // Not bound to setting change when emptying.
 		}
 	});
 
 	/**
 	 * An upload control, which utilizes the media modal.
 	 *
 	 * @class    wp.customize.UploadControl
 	 * @augments wp.customize.MediaControl
 	 */
 	api.UploadControl = api.MediaControl.extend(/** @lends wp.customize.UploadControl.prototype */{
 
 		/**
 		 * Callback handler for when an attachment is selected in the media modal.
 		 * Gets the selected image information, and sets it within the control.
 		 */
 		select: function() {
 			// Get the attachment from the modal frame.
 			var node,
 				attachment = this.frame.state().get( 'selection' ).first().toJSON(),
 				mejsSettings = window._wpmejsSettings || {};
 
 			this.params.attachment = attachment;
 
 			// Set the Customizer setting; the callback takes care of rendering.
 			this.setting( attachment.url );
 			node = this.container.find( 'audio, video' ).get(0);
 
 			// Initialize audio/video previews.
 			if ( node ) {
 				this.player = new MediaElementPlayer( node, mejsSettings );
 			} else {
 				this.cleanupPlayer();
 			}
 		},
 
 		// @deprecated
 		success: function() {},
 
 		// @deprecated
 		removerVisibility: function() {}
 	});
 
 	/**
 	 * A control for uploading images.
 	 *
 	 * This control no longer needs to do anything more
 	 * than what the upload control does in JS.
 	 *
 	 * @class    wp.customize.ImageControl
 	 * @augments wp.customize.UploadControl
 	 */
 	api.ImageControl = api.UploadControl.extend(/** @lends wp.customize.ImageControl.prototype */{
 		// @deprecated
 		thumbnailSrc: function() {}
 	});
 
 	/**
 	 * A control for uploading background images.
 	 *
 	 * @class    wp.customize.BackgroundControl
 	 * @augments wp.customize.UploadControl
 	 */
 	api.BackgroundControl = api.UploadControl.extend(/** @lends wp.customize.BackgroundControl.prototype */{
 
 		/**
 		 * When the control's DOM structure is ready,
 		 * set up internal event bindings.
 		 */
 		ready: function() {
 			api.UploadControl.prototype.ready.apply( this, arguments );
 		},
 
 		/**
 		 * Callback handler for when an attachment is selected in the media modal.
 		 * Does an additional Ajax request for setting the background context.
 		 */
 		select: function() {
 			api.UploadControl.prototype.select.apply( this, arguments );
 
 			wp.ajax.post( 'custom-background-add', {
 				nonce: _wpCustomizeBackground.nonces.add,
 				wp_customize: 'on',
 				customize_theme: api.settings.theme.stylesheet,
 				attachment_id: this.params.attachment.id
 			} );
 		}
 	});
 
 	/**
 	 * A control for positioning a background image.
 	 *
 	 * @since 4.7.0
 	 *
 	 * @class    wp.customize.BackgroundPositionControl
 	 * @augments wp.customize.Control
 	 */
 	api.BackgroundPositionControl = api.Control.extend(/** @lends wp.customize.BackgroundPositionControl.prototype */{
 
 		/**
 		 * Set up control UI once embedded in DOM and settings are created.
 		 *
 		 * @since 4.7.0
 		 * @access public
 		 */
 		ready: function() {
 			var control = this, updateRadios;
 
 			control.container.on( 'change', 'input[name="background-position"]', function() {
 				var position = $( this ).val().split( ' ' );
 				control.settings.x( position[0] );
 				control.settings.y( position[1] );
 			} );
 
 			updateRadios = _.debounce( function() {
 				var x, y, radioInput, inputValue;
 				x = control.settings.x.get();
 				y = control.settings.y.get();
 				inputValue = String( x ) + ' ' + String( y );
 				radioInput = control.container.find( 'input[name="background-position"][value="' + inputValue + '"]' );
 				radioInput.trigger( 'click' );
 			} );
 			control.settings.x.bind( updateRadios );
 			control.settings.y.bind( updateRadios );
 
 			updateRadios(); // Set initial UI.
 		}
 	} );
 
 	/**
 	 * A control for selecting and cropping an image.
 	 *
 	 * @class    wp.customize.CroppedImageControl
 	 * @augments wp.customize.MediaControl
 	 */
 	api.CroppedImageControl = api.MediaControl.extend(/** @lends wp.customize.CroppedImageControl.prototype */{
 
 		/**
 		 * Open the media modal to the library state.
 		 */
 		openFrame: function( event ) {
 			if ( api.utils.isKeydownButNotEnterEvent( event ) ) {
 				return;
 			}
 
 			this.initFrame();
 			this.frame.setState( 'library' ).open();
 		},
 
 		/**
 		 * Create a media modal select frame, and store it so the instance can be reused when needed.
 		 */
 		initFrame: function() {
 			var l10n = _wpMediaViewsL10n;
 
 			this.frame = wp.media({
 				button: {
 					text: l10n.select,
 					close: false
 				},
 				states: [
 					new wp.media.controller.Library({
 						title: this.params.button_labels.frame_title,
 						library: wp.media.query({ type: 'image' }),
 						multiple: false,
 						date: false,
 						priority: 20,
 						suggestedWidth: this.params.width,
 						suggestedHeight: this.params.height
 					}),
 					new wp.media.controller.CustomizeImageCropper({
 						imgSelectOptions: this.calculateImageSelectOptions,
 						control: this
 					})
 				]
 			});
 
 			this.frame.on( 'select', this.onSelect, this );
 			this.frame.on( 'cropped', this.onCropped, this );
 			this.frame.on( 'skippedcrop', this.onSkippedCrop, this );
 		},
 
 		/**
 		 * After an image is selected in the media modal, switch to the cropper
 		 * state if the image isn't the right size.
 		 */
 		onSelect: function() {
 			var attachment = this.frame.state().get( 'selection' ).first().toJSON();
 
 			if ( this.params.width === attachment.width && this.params.height === attachment.height && ! this.params.flex_width && ! this.params.flex_height ) {
 				this.setImageFromAttachment( attachment );
 				this.frame.close();
 			} else {
 				this.frame.setState( 'cropper' );
 			}
 		},
 
 		/**
 		 * After the image has been cropped, apply the cropped image data to the setting.
 		 *
 		 * @param {Object} croppedImage Cropped attachment data.
 		 */
 		onCropped: function( croppedImage ) {
 			this.setImageFromAttachment( croppedImage );
 		},
 
 		/**
 		 * Returns a set of options, computed from the attached image data and
 		 * control-specific data, to be fed to the imgAreaSelect plugin in
 		 * wp.media.view.Cropper.
 		 *
 		 * @param {wp.media.model.Attachment} attachment
 		 * @param {wp.media.controller.Cropper} controller
 		 * @return {Object} Options
 		 */
 		calculateImageSelectOptions: function( attachment, controller ) {
 			var control    = controller.get( 'control' ),
 				flexWidth  = !! parseInt( control.params.flex_width, 10 ),
 				flexHeight = !! parseInt( control.params.flex_height, 10 ),
 				realWidth  = attachment.get( 'width' ),
 				realHeight = attachment.get( 'height' ),
 				xInit = parseInt( control.params.width, 10 ),
 				yInit = parseInt( control.params.height, 10 ),
 				ratio = xInit / yInit,
 				xImg  = xInit,
 				yImg  = yInit,
 				x1, y1, imgSelectOptions;
 
 			controller.set( 'canSkipCrop', ! control.mustBeCropped( flexWidth, flexHeight, xInit, yInit, realWidth, realHeight ) );
 
 			if ( realWidth / realHeight > ratio ) {
 				yInit = realHeight;
 				xInit = yInit * ratio;
 			} else {
 				xInit = realWidth;
 				yInit = xInit / ratio;
 			}
 
 			x1 = ( realWidth - xInit ) / 2;
 			y1 = ( realHeight - yInit ) / 2;
 
 			imgSelectOptions = {
 				handles: true,
 				keys: true,
 				instance: true,
 				persistent: true,
 				imageWidth: realWidth,
 				imageHeight: realHeight,
 				minWidth: xImg > xInit ? xInit : xImg,
 				minHeight: yImg > yInit ? yInit : yImg,
 				x1: x1,
 				y1: y1,
 				x2: xInit + x1,
 				y2: yInit + y1
 			};
 
 			if ( flexHeight === false && flexWidth === false ) {
 				imgSelectOptions.aspectRatio = xInit + ':' + yInit;
 			}
 
 			if ( true === flexHeight ) {
 				delete imgSelectOptions.minHeight;
 				imgSelectOptions.maxWidth = realWidth;
 			}
 
 			if ( true === flexWidth ) {
 				delete imgSelectOptions.minWidth;
 				imgSelectOptions.maxHeight = realHeight;
 			}
 
 			return imgSelectOptions;
 		},
 
 		/**
 		 * Return whether the image must be cropped, based on required dimensions.
 		 *
 		 * @param {boolean} flexW
 		 * @param {boolean} flexH
 		 * @param {number}  dstW
 		 * @param {number}  dstH
 		 * @param {number}  imgW
 		 * @param {number}  imgH
 		 * @return {boolean}
 		 */
 		mustBeCropped: function( flexW, flexH, dstW, dstH, imgW, imgH ) {
 			if ( true === flexW && true === flexH ) {
 				return false;
 			}
 
 			if ( true === flexW && dstH === imgH ) {
 				return false;
 			}
 
 			if ( true === flexH && dstW === imgW ) {
 				return false;
 			}
 
 			if ( dstW === imgW && dstH === imgH ) {
 				return false;
 			}
 
 			if ( imgW <= dstW ) {
 				return false;
 			}
 
 			return true;
 		},
 
 		/**
 		 * If cropping was skipped, apply the image data directly to the setting.
 		 */
 		onSkippedCrop: function() {
 			var attachment = this.frame.state().get( 'selection' ).first().toJSON();
 			this.setImageFromAttachment( attachment );
 		},
 
 		/**
 		 * Updates the setting and re-renders the control UI.
 		 *
 		 * @param {Object} attachment
 		 */
 		setImageFromAttachment: function( attachment ) {
 			this.params.attachment = attachment;
 
 			// Set the Customizer setting; the callback takes care of rendering.
 			this.setting( attachment.id );
 		}
 	});
 
 	/**
 	 * A control for selecting and cropping Site Icons.
 	 *
 	 * @class    wp.customize.SiteIconControl
 	 * @augments wp.customize.CroppedImageControl
 	 */
 	api.SiteIconControl = api.CroppedImageControl.extend(/** @lends wp.customize.SiteIconControl.prototype */{
 
 		/**
 		 * Create a media modal select frame, and store it so the instance can be reused when needed.
 		 */
 		initFrame: function() {
 			var l10n = _wpMediaViewsL10n;
 
 			this.frame = wp.media({
 				button: {
 					text: l10n.select,
 					close: false
 				},
 				states: [
 					new wp.media.controller.Library({
 						title: this.params.button_labels.frame_title,
 						library: wp.media.query({ type: 'image' }),
 						multiple: false,
 						date: false,
 						priority: 20,
 						suggestedWidth: this.params.width,
 						suggestedHeight: this.params.height
 					}),
 					new wp.media.controller.SiteIconCropper({
 						imgSelectOptions: this.calculateImageSelectOptions,
 						control: this
 					})
 				]
 			});
 
 			this.frame.on( 'select', this.onSelect, this );
 			this.frame.on( 'cropped', this.onCropped, this );
 			this.frame.on( 'skippedcrop', this.onSkippedCrop, this );
 		},
 
 		/**
 		 * After an image is selected in the media modal, switch to the cropper
 		 * state if the image isn't the right size.
 		 */
 		onSelect: function() {
 			var attachment = this.frame.state().get( 'selection' ).first().toJSON(),
 				controller = this;
 
 			if ( this.params.width === attachment.width && this.params.height === attachment.height && ! this.params.flex_width && ! this.params.flex_height ) {
 				wp.ajax.post( 'crop-image', {
 					nonce: attachment.nonces.edit,
 					id: attachment.id,
 					context: 'site-icon',
 					cropDetails: {
 						x1: 0,
 						y1: 0,
 						width: this.params.width,
 						height: this.params.height,
 						dst_width: this.params.width,
 						dst_height: this.params.height
 					}
 				} ).done( function( croppedImage ) {
 					controller.setImageFromAttachment( croppedImage );
 					controller.frame.close();
 				} ).fail( function() {
 					controller.frame.trigger('content:error:crop');
 				} );
 			} else {
 				this.frame.setState( 'cropper' );
 			}
 		},
 
 		/**
 		 * Updates the setting and re-renders the control UI.
 		 *
 		 * @param {Object} attachment
 		 */
 		setImageFromAttachment: function( attachment ) {
 			var sizes = [ 'site_icon-32', 'thumbnail', 'full' ], link,
 				icon;
 
 			_.each( sizes, function( size ) {
 				if ( ! icon && ! _.isUndefined ( attachment.sizes[ size ] ) ) {
 					icon = attachment.sizes[ size ];
 				}
 			} );
 
 			this.params.attachment = attachment;
 
 			// Set the Customizer setting; the callback takes care of rendering.
 			this.setting( attachment.id );
 
 			if ( ! icon ) {
 				return;
 			}
 
 			// Update the icon in-browser.
 			link = $( 'link[rel="icon"][sizes="32x32"]' );
 			link.attr( 'href', icon.url );
 		},
 
 		/**
 		 * Called when the "Remove" link is clicked. Empties the setting.
 		 *
 		 * @param {Object} event jQuery Event object
 		 */
 		removeFile: function( event ) {
 			if ( api.utils.isKeydownButNotEnterEvent( event ) ) {
 				return;
 			}
 			event.preventDefault();
 
 			this.params.attachment = {};
 			this.setting( '' );
 			this.renderContent(); // Not bound to setting change when emptying.
 			$( 'link[rel="icon"][sizes="32x32"]' ).attr( 'href', '/favicon.ico' ); // Set to default.
 		}
 	});
 
 	/**
 	 * @class    wp.customize.HeaderControl
 	 * @augments wp.customize.Control
 	 */
 	api.HeaderControl = api.Control.extend(/** @lends wp.customize.HeaderControl.prototype */{
 		ready: function() {
 			this.btnRemove = $('#customize-control-header_image .actions .remove');
 			this.btnNew    = $('#customize-control-header_image .actions .new');
 
 			_.bindAll(this, 'openMedia', 'removeImage');
 
 			this.btnNew.on( 'click', this.openMedia );
 			this.btnRemove.on( 'click', this.removeImage );
 
 			api.HeaderTool.currentHeader = this.getInitialHeaderImage();
 
 			new api.HeaderTool.CurrentView({
 				model: api.HeaderTool.currentHeader,
 				el: '#customize-control-header_image .current .container'
 			});
 
 			new api.HeaderTool.ChoiceListView({
 				collection: api.HeaderTool.UploadsList = new api.HeaderTool.ChoiceList(),
 				el: '#customize-control-header_image .choices .uploaded .list'
 			});
 
 			new api.HeaderTool.ChoiceListView({
 				collection: api.HeaderTool.DefaultsList = new api.HeaderTool.DefaultsList(),
 				el: '#customize-control-header_image .choices .default .list'
 			});
 
 			api.HeaderTool.combinedList = api.HeaderTool.CombinedList = new api.HeaderTool.CombinedList([
 				api.HeaderTool.UploadsList,
 				api.HeaderTool.DefaultsList
 			]);
 
 			// Ensure custom-header-crop Ajax requests bootstrap the Customizer to activate the previewed theme.
 			wp.media.controller.Cropper.prototype.defaults.doCropArgs.wp_customize = 'on';
 			wp.media.controller.Cropper.prototype.defaults.doCropArgs.customize_theme = api.settings.theme.stylesheet;
 		},
 
 		/**
 		 * Returns a new instance of api.HeaderTool.ImageModel based on the currently
 		 * saved header image (if any).
 		 *
 		 * @since 4.2.0
 		 *
 		 * @return {Object} Options
 		 */
 		getInitialHeaderImage: function() {
 			if ( ! api.get().header_image || ! api.get().header_image_data || _.contains( [ 'remove-header', 'random-default-image', 'random-uploaded-image' ], api.get().header_image ) ) {
 				return new api.HeaderTool.ImageModel();
 			}
 
 			// Get the matching uploaded image object.
 			var currentHeaderObject = _.find( _wpCustomizeHeader.uploads, function( imageObj ) {
 				return ( imageObj.attachment_id === api.get().header_image_data.attachment_id );
 			} );
 			// Fall back to raw current header image.
 			if ( ! currentHeaderObject ) {
 				currentHeaderObject = {
 					url: api.get().header_image,
 					thumbnail_url: api.get().header_image,
 					attachment_id: api.get().header_image_data.attachment_id
 				};
 			}
 
 			return new api.HeaderTool.ImageModel({
 				header: currentHeaderObject,
 				choice: currentHeaderObject.url.split( '/' ).pop()
 			});
 		},
 
 		/**
 		 * Returns a set of options, computed from the attached image data and
 		 * theme-specific data, to be fed to the imgAreaSelect plugin in
 		 * wp.media.view.Cropper.
 		 *
 		 * @param {wp.media.model.Attachment} attachment
 		 * @param {wp.media.controller.Cropper} controller
 		 * @return {Object} Options
 		 */
 		calculateImageSelectOptions: function(attachment, controller) {
 			var xInit = parseInt(_wpCustomizeHeader.data.width, 10),
 				yInit = parseInt(_wpCustomizeHeader.data.height, 10),
 				flexWidth = !! parseInt(_wpCustomizeHeader.data['flex-width'], 10),
 				flexHeight = !! parseInt(_wpCustomizeHeader.data['flex-height'], 10),
 				ratio, xImg, yImg, realHeight, realWidth,
 				imgSelectOptions;
 
 			realWidth = attachment.get('width');
 			realHeight = attachment.get('height');
 
 			this.headerImage = new api.HeaderTool.ImageModel();
 			this.headerImage.set({
 				themeWidth: xInit,
 				themeHeight: yInit,
 				themeFlexWidth: flexWidth,
 				themeFlexHeight: flexHeight,
 				imageWidth: realWidth,
 				imageHeight: realHeight
 			});
 
 			controller.set( 'canSkipCrop', ! this.headerImage.shouldBeCropped() );
 
 			ratio = xInit / yInit;
 			xImg = realWidth;
 			yImg = realHeight;
 
 			if ( xImg / yImg > ratio ) {
 				yInit = yImg;
 				xInit = yInit * ratio;
 			} else {
 				xInit = xImg;
 				yInit = xInit / ratio;
 			}
 
 			imgSelectOptions = {
 				handles: true,
 				keys: true,
 				instance: true,
 				persistent: true,
 				imageWidth: realWidth,
 				imageHeight: realHeight,
 				x1: 0,
 				y1: 0,
 				x2: xInit,
 				y2: yInit
 			};
 
 			if (flexHeight === false && flexWidth === false) {
 				imgSelectOptions.aspectRatio = xInit + ':' + yInit;
 			}
 			if (flexHeight === false ) {
 				imgSelectOptions.maxHeight = yInit;
 			}
 			if (flexWidth === false ) {
 				imgSelectOptions.maxWidth = xInit;
 			}
 
 			return imgSelectOptions;
 		},
 
 		/**
 		 * Sets up and opens the Media Manager in order to select an image.
 		 * Depending on both the size of the image and the properties of the
 		 * current theme, a cropping step after selection may be required or
 		 * skippable.
 		 *
 		 * @param {event} event
 		 */
 		openMedia: function(event) {
 			var l10n = _wpMediaViewsL10n;
 
 			event.preventDefault();
 
 			this.frame = wp.media({
 				button: {
 					text: l10n.selectAndCrop,
 					close: false
 				},
 				states: [
 					new wp.media.controller.Library({
 						title:     l10n.chooseImage,
 						library:   wp.media.query({ type: 'image' }),
 						multiple:  false,
 						date:      false,
 						priority:  20,
 						suggestedWidth: _wpCustomizeHeader.data.width,
 						suggestedHeight: _wpCustomizeHeader.data.height
 					}),
 					new wp.media.controller.Cropper({
 						imgSelectOptions: this.calculateImageSelectOptions
 					})
 				]
 			});
 
 			this.frame.on('select', this.onSelect, this);
 			this.frame.on('cropped', this.onCropped, this);
 			this.frame.on('skippedcrop', this.onSkippedCrop, this);
 
 			this.frame.open();
 		},
 
 		/**
 		 * After an image is selected in the media modal,
 		 * switch to the cropper state.
 		 */
 		onSelect: function() {
 			this.frame.setState('cropper');
 		},
 
 		/**
 		 * After the image has been cropped, apply the cropped image data to the setting.
 		 *
 		 * @param {Object} croppedImage Cropped attachment data.
 		 */
 		onCropped: function(croppedImage) {
 			var url = croppedImage.url,
 				attachmentId = croppedImage.attachment_id,
 				w = croppedImage.width,
 				h = croppedImage.height;
 			this.setImageFromURL(url, attachmentId, w, h);
 		},
 
 		/**
 		 * If cropping was skipped, apply the image data directly to the setting.
 		 *
 		 * @param {Object} selection
 		 */
 		onSkippedCrop: function(selection) {
 			var url = selection.get('url'),
 				w = selection.get('width'),
 				h = selection.get('height');
 			this.setImageFromURL(url, selection.id, w, h);
 		},
 
 		/**
 		 * Creates a new wp.customize.HeaderTool.ImageModel from provided
 		 * header image data and inserts it into the user-uploaded headers
 		 * collection.
 		 *
 		 * @param {string} url
 		 * @param {number} attachmentId
 		 * @param {number} width
 		 * @param {number} height
 		 */
 		setImageFromURL: function(url, attachmentId, width, height) {
 			var choice, data = {};
 
 			data.url = url;
 			data.thumbnail_url = url;
 			data.timestamp = _.now();
 
 			if (attachmentId) {
 				data.attachment_id = attachmentId;
 			}
 
 			if (width) {
 				data.width = width;
 			}
 
 			if (height) {
 				data.height = height;
 			}
 
 			choice = new api.HeaderTool.ImageModel({
 				header: data,
 				choice: url.split('/').pop()
 			});
 			api.HeaderTool.UploadsList.add(choice);
 			api.HeaderTool.currentHeader.set(choice.toJSON());
 			choice.save();
 			choice.importImage();
 		},
 
 		/**
 		 * Triggers the necessary events to deselect an image which was set as
 		 * the currently selected one.
 		 */
 		removeImage: function() {
 			api.HeaderTool.currentHeader.trigger('hide');
 			api.HeaderTool.CombinedList.trigger('control:removeImage');
 		}
 
 	});
 
 	/**
 	 * wp.customize.ThemeControl
 	 *
 	 * @class    wp.customize.ThemeControl
 	 * @augments wp.customize.Control
 	 */
 	api.ThemeControl = api.Control.extend(/** @lends wp.customize.ThemeControl.prototype */{
 
 		touchDrag: false,
 		screenshotRendered: false,
 
 		/**
 		 * @since 4.2.0
 		 */
 		ready: function() {
 			var control = this, panel = api.panel( 'themes' );
 
 			function disableSwitchButtons() {
 				return ! panel.canSwitchTheme( control.params.theme.id );
 			}
 
 			// Temporary special function since supplying SFTP credentials does not work yet. See #42184.
 			function disableInstallButtons() {
 				return disableSwitchButtons() || false === api.settings.theme._canInstall || true === api.settings.theme._filesystemCredentialsNeeded;
 			}
 			function updateButtons() {
 				control.container.find( 'button.preview, button.preview-theme' ).toggleClass( 'disabled', disableSwitchButtons() );
 				control.container.find( 'button.theme-install' ).toggleClass( 'disabled', disableInstallButtons() );
 			}
 
 			api.state( 'selectedChangesetStatus' ).bind( updateButtons );
 			api.state( 'changesetStatus' ).bind( updateButtons );
 			updateButtons();
 
 			control.container.on( 'touchmove', '.theme', function() {
 				control.touchDrag = true;
 			});
 
 			// Bind details view trigger.
 			control.container.on( 'click keydown touchend', '.theme', function( event ) {
 				var section;
 				if ( api.utils.isKeydownButNotEnterEvent( event ) ) {
 					return;
 				}
 
 				// Bail if the user scrolled on a touch device.
 				if ( control.touchDrag === true ) {
 					return control.touchDrag = false;
 				}
 
 				// Prevent the modal from showing when the user clicks the action button.
 				if ( $( event.target ).is( '.theme-actions .button, .update-theme' ) ) {
 					return;
 				}
 
 				event.preventDefault(); // Keep this AFTER the key filter above.
 				section = api.section( control.section() );
 				section.showDetails( control.params.theme, function() {
 
 					// Temporary special function since supplying SFTP credentials does not work yet. See #42184.
 					if ( api.settings.theme._filesystemCredentialsNeeded ) {
 						section.overlay.find( '.theme-actions .delete-theme' ).remove();
 					}
 				} );
 			});
 
 			control.container.on( 'render-screenshot', function() {
 				var $screenshot = $( this ).find( 'img' ),
 					source = $screenshot.data( 'src' );
 
 				if ( source ) {
 					$screenshot.attr( 'src', source );
 				}
 				control.screenshotRendered = true;
 			});
 		},
 
 		/**
 		 * Show or hide the theme based on the presence of the term in the title, description, tags, and author.
 		 *
 		 * @since 4.2.0
 		 * @param {Array} terms - An array of terms to search for.
 		 * @return {boolean} Whether a theme control was activated or not.
 		 */
 		filter: function( terms ) {
 			var control = this,
 				matchCount = 0,
 				haystack = control.params.theme.name + ' ' +
 					control.params.theme.description + ' ' +
 					control.params.theme.tags + ' ' +
 					control.params.theme.author + ' ';
 			haystack = haystack.toLowerCase().replace( '-', ' ' );
 
 			// Back-compat for behavior in WordPress 4.2.0 to 4.8.X.
 			if ( ! _.isArray( terms ) ) {
 				terms = [ terms ];
 			}
 
 			// Always give exact name matches highest ranking.
 			if ( control.params.theme.name.toLowerCase() === terms.join( ' ' ) ) {
 				matchCount = 100;
 			} else {
 
 				// Search for and weight (by 10) complete term matches.
 				matchCount = matchCount + 10 * ( haystack.split( terms.join( ' ' ) ).length - 1 );
 
 				// Search for each term individually (as whole-word and partial match) and sum weighted match counts.
 				_.each( terms, function( term ) {
 					matchCount = matchCount + 2 * ( haystack.split( term + ' ' ).length - 1 ); // Whole-word, double-weighted.
 					matchCount = matchCount + haystack.split( term ).length - 1; // Partial word, to minimize empty intermediate searches while typing.
 				});
 
 				// Upper limit on match ranking.
 				if ( matchCount > 99 ) {
 					matchCount = 99;
 				}
 			}
 
 			if ( 0 !== matchCount ) {
 				control.activate();
 				control.params.priority = 101 - matchCount; // Sort results by match count.
 				return true;
 			} else {
 				control.deactivate(); // Hide control.
 				control.params.priority = 101;
 				return false;
 			}
 		},
 
 		/**
 		 * Rerender the theme from its JS template with the installed type.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @return {void}
 		 */
 		rerenderAsInstalled: function( installed ) {
 			var control = this, section;
 			if ( installed ) {
 				control.params.theme.type = 'installed';
 			} else {
 				section = api.section( control.params.section );
 				control.params.theme.type = section.params.action;
 			}
 			control.renderContent(); // Replaces existing content.
 			control.container.trigger( 'render-screenshot' );
 		}
 	});
 
 	/**
 	 * Class wp.customize.CodeEditorControl
 	 *
 	 * @since 4.9.0
 	 *
 	 * @class    wp.customize.CodeEditorControl
 	 * @augments wp.customize.Control
 	 */
 	api.CodeEditorControl = api.Control.extend(/** @lends wp.customize.CodeEditorControl.prototype */{
 
 		/**
 		 * Initialize.
 		 *
 		 * @since 4.9.0
 		 * @param {string} id      - Unique identifier for the control instance.
 		 * @param {Object} options - Options hash for the control instance.
 		 * @return {void}
 		 */
 		initialize: function( id, options ) {
 			var control = this;
 			control.deferred = _.extend( control.deferred || {}, {
 				codemirror: $.Deferred()
 			} );
 			api.Control.prototype.initialize.call( control, id, options );
 
 			// Note that rendering is debounced so the props will be used when rendering happens after add event.
 			control.notifications.bind( 'add', function( notification ) {
 
 				// Skip if control notification is not from setting csslint_error notification.
 				if ( notification.code !== control.setting.id + ':csslint_error' ) {
 					return;
 				}
 
 				// Customize the template and behavior of csslint_error notifications.
 				notification.templateId = 'customize-code-editor-lint-error-notification';
 				notification.render = (function( render ) {
 					return function() {
 						var li = render.call( this );
 						li.find( 'input[type=checkbox]' ).on( 'click', function() {
 							control.setting.notifications.remove( 'csslint_error' );
 						} );
 						return li;
 					};
 				})( notification.render );
 			} );
 		},
 
 		/**
 		 * Initialize the editor when the containing section is ready and expanded.
 		 *
 		 * @since 4.9.0
 		 * @return {void}
 		 */
 		ready: function() {
 			var control = this;
 			if ( ! control.section() ) {
 				control.initEditor();
 				return;
 			}
 
 			// Wait to initialize editor until section is embedded and expanded.
 			api.section( control.section(), function( section ) {
 				section.deferred.embedded.done( function() {
 					var onceExpanded;
 					if ( section.expanded() ) {
 						control.initEditor();
 					} else {
 						onceExpanded = function( isExpanded ) {
 							if ( isExpanded ) {
 								control.initEditor();
 								section.expanded.unbind( onceExpanded );
 							}
 						};
 						section.expanded.bind( onceExpanded );
 					}
 				} );
 			} );
 		},
 
 		/**
 		 * Initialize editor.
 		 *
 		 * @since 4.9.0
 		 * @return {void}
 		 */
 		initEditor: function() {
 			var control = this, element, editorSettings = false;
 
 			// Obtain editorSettings for instantiation.
 			if ( wp.codeEditor && ( _.isUndefined( control.params.editor_settings ) || false !== control.params.editor_settings ) ) {
 
 				// Obtain default editor settings.
 				editorSettings = wp.codeEditor.defaultSettings ? _.clone( wp.codeEditor.defaultSettings ) : {};
 				editorSettings.codemirror = _.extend(
 					{},
 					editorSettings.codemirror,
 					{
 						indentUnit: 2,
 						tabSize: 2
 					}
 				);
 
 				// Merge editor_settings param on top of defaults.
 				if ( _.isObject( control.params.editor_settings ) ) {
 					_.each( control.params.editor_settings, function( value, key ) {
 						if ( _.isObject( value ) ) {
 							editorSettings[ key ] = _.extend(
 								{},
 								editorSettings[ key ],
 								value
 							);
 						}
 					} );
 				}
 			}
 
 			element = new api.Element( control.container.find( 'textarea' ) );
 			control.elements.push( element );
 			element.sync( control.setting );
 			element.set( control.setting() );
 
 			if ( editorSettings ) {
 				control.initSyntaxHighlightingEditor( editorSettings );
 			} else {
 				control.initPlainTextareaEditor();
 			}
 		},
 
 		/**
 		 * Make sure editor gets focused when control is focused.
 		 *
 		 * @since 4.9.0
 		 * @param {Object}   [params] - Focus params.
 		 * @param {Function} [params.completeCallback] - Function to call when expansion is complete.
 		 * @return {void}
 		 */
 		focus: function( params ) {
 			var control = this, extendedParams = _.extend( {}, params ), originalCompleteCallback;
 			originalCompleteCallback = extendedParams.completeCallback;
 			extendedParams.completeCallback = function() {
 				if ( originalCompleteCallback ) {
 					originalCompleteCallback();
 				}
 				if ( control.editor ) {
 					control.editor.codemirror.focus();
 				}
 			};
 			api.Control.prototype.focus.call( control, extendedParams );
 		},
 
 		/**
 		 * Initialize syntax-highlighting editor.
 		 *
 		 * @since 4.9.0
 		 * @param {Object} codeEditorSettings - Code editor settings.
 		 * @return {void}
 		 */
 		initSyntaxHighlightingEditor: function( codeEditorSettings ) {
 			var control = this, $textarea = control.container.find( 'textarea' ), settings, suspendEditorUpdate = false;
 
 			settings = _.extend( {}, codeEditorSettings, {
 				onTabNext: _.bind( control.onTabNext, control ),
 				onTabPrevious: _.bind( control.onTabPrevious, control ),
 				onUpdateErrorNotice: _.bind( control.onUpdateErrorNotice, control )
 			});
 
 			control.editor = wp.codeEditor.initialize( $textarea, settings );
 
 			// Improve the editor accessibility.
 			$( control.editor.codemirror.display.lineDiv )
 				.attr({
 					role: 'textbox',
 					'aria-multiline': 'true',
 					'aria-label': control.params.label,
 					'aria-describedby': 'editor-keyboard-trap-help-1 editor-keyboard-trap-help-2 editor-keyboard-trap-help-3 editor-keyboard-trap-help-4'
 				});
 
 			// Focus the editor when clicking on its label.
 			control.container.find( 'label' ).on( 'click', function() {
 				control.editor.codemirror.focus();
 			});
 
 			/*
 			 * When the CodeMirror instance changes, mirror to the textarea,
 			 * where we have our "true" change event handler bound.
 			 */
 			control.editor.codemirror.on( 'change', function( codemirror ) {
 				suspendEditorUpdate = true;
 				$textarea.val( codemirror.getValue() ).trigger( 'change' );
 				suspendEditorUpdate = false;
 			});
 
 			// Update CodeMirror when the setting is changed by another plugin.
 			control.setting.bind( function( value ) {
 				if ( ! suspendEditorUpdate ) {
 					control.editor.codemirror.setValue( value );
 				}
 			});
 
 			// Prevent collapsing section when hitting Esc to tab out of editor.
 			control.editor.codemirror.on( 'keydown', function onKeydown( codemirror, event ) {
 				var escKeyCode = 27;
 				if ( escKeyCode === event.keyCode ) {
 					event.stopPropagation();
 				}
 			});
 
 			control.deferred.codemirror.resolveWith( control, [ control.editor.codemirror ] );
 		},
 
 		/**
 		 * Handle tabbing to the field after the editor.
 		 *
 		 * @since 4.9.0
 		 * @return {void}
 		 */
 		onTabNext: function onTabNext() {
 			var control = this, controls, controlIndex, section;
 			section = api.section( control.section() );
 			controls = section.controls();
 			controlIndex = controls.indexOf( control );
 			if ( controls.length === controlIndex + 1 ) {
 				$( '#customize-footer-actions .collapse-sidebar' ).trigger( 'focus' );
 			} else {
 				controls[ controlIndex + 1 ].container.find( ':focusable:first' ).focus();
 			}
 		},
 
 		/**
 		 * Handle tabbing to the field before the editor.
 		 *
 		 * @since 4.9.0
 		 * @return {void}
 		 */
 		onTabPrevious: function onTabPrevious() {
 			var control = this, controls, controlIndex, section;
 			section = api.section( control.section() );
 			controls = section.controls();
 			controlIndex = controls.indexOf( control );
 			if ( 0 === controlIndex ) {
 				section.contentContainer.find( '.customize-section-title .customize-help-toggle, .customize-section-title .customize-section-description.open .section-description-close' ).last().focus();
 			} else {
 				controls[ controlIndex - 1 ].contentContainer.find( ':focusable:first' ).focus();
 			}
 		},
 
 		/**
 		 * Update error notice.
 		 *
 		 * @since 4.9.0
 		 * @param {Array} errorAnnotations - Error annotations.
 		 * @return {void}
 		 */
 		onUpdateErrorNotice: function onUpdateErrorNotice( errorAnnotations ) {
 			var control = this, message;
 			control.setting.notifications.remove( 'csslint_error' );
 
 			if ( 0 !== errorAnnotations.length ) {
 				if ( 1 === errorAnnotations.length ) {
 					message = api.l10n.customCssError.singular.replace( '%d', '1' );
 				} else {
 					message = api.l10n.customCssError.plural.replace( '%d', String( errorAnnotations.length ) );
 				}
 				control.setting.notifications.add( new api.Notification( 'csslint_error', {
 					message: message,
 					type: 'error'
 				} ) );
 			}
 		},
 
 		/**
 		 * Initialize plain-textarea editor when syntax highlighting is disabled.
 		 *
 		 * @since 4.9.0
 		 * @return {void}
 		 */
 		initPlainTextareaEditor: function() {
 			var control = this, $textarea = control.container.find( 'textarea' ), textarea = $textarea[0];
 
 			$textarea.on( 'blur', function onBlur() {
 				$textarea.data( 'next-tab-blurs', false );
 			} );
 
 			$textarea.on( 'keydown', function onKeydown( event ) {
 				var selectionStart, selectionEnd, value, tabKeyCode = 9, escKeyCode = 27;
 
 				if ( escKeyCode === event.keyCode ) {
 					if ( ! $textarea.data( 'next-tab-blurs' ) ) {
 						$textarea.data( 'next-tab-blurs', true );
 						event.stopPropagation(); // Prevent collapsing the section.
 					}
 					return;
 				}
 
 				// Short-circuit if tab key is not being pressed or if a modifier key *is* being pressed.
 				if ( tabKeyCode !== event.keyCode || event.ctrlKey || event.altKey || event.shiftKey ) {
 					return;
 				}
 
 				// Prevent capturing Tab characters if Esc was pressed.
 				if ( $textarea.data( 'next-tab-blurs' ) ) {
 					return;
 				}
 
 				selectionStart = textarea.selectionStart;
 				selectionEnd = textarea.selectionEnd;
 				value = textarea.value;
 
 				if ( selectionStart >= 0 ) {
 					textarea.value = value.substring( 0, selectionStart ).concat( '\t', value.substring( selectionEnd ) );
 					$textarea.selectionStart = textarea.selectionEnd = selectionStart + 1;
 				}
 
 				event.stopPropagation();
 				event.preventDefault();
 			});
 
 			control.deferred.codemirror.rejectWith( control );
 		}
 	});
 
 	/**
 	 * Class wp.customize.DateTimeControl.
 	 *
 	 * @since 4.9.0
 	 * @class    wp.customize.DateTimeControl
 	 * @augments wp.customize.Control
 	 */
 	api.DateTimeControl = api.Control.extend(/** @lends wp.customize.DateTimeControl.prototype */{
 
 		/**
 		 * Initialize behaviors.
 		 *
 		 * @since 4.9.0
 		 * @return {void}
 		 */
 		ready: function ready() {
 			var control = this;
 
 			control.inputElements = {};
 			control.invalidDate = false;
 
 			_.bindAll( control, 'populateSetting', 'updateDaysForMonth', 'populateDateInputs' );
 
 			if ( ! control.setting ) {
 				throw new Error( 'Missing setting' );
 			}
 
 			control.container.find( '.date-input' ).each( function() {
 				var input = $( this ), component, element;
 				component = input.data( 'component' );
 				element = new api.Element( input );
 				control.inputElements[ component ] = element;
 				control.elements.push( element );
 
 				// Add invalid date error once user changes (and has blurred the input).
 				input.on( 'change', function() {
 					if ( control.invalidDate ) {
 						control.notifications.add( new api.Notification( 'invalid_date', {
 							message: api.l10n.invalidDate
 						} ) );
 					}
 				} );
 
 				// Remove the error immediately after validity change.
 				input.on( 'input', _.debounce( function() {
 					if ( ! control.invalidDate ) {
 						control.notifications.remove( 'invalid_date' );
 					}
 				} ) );
 
 				// Add zero-padding when blurring field.
 				input.on( 'blur', _.debounce( function() {
 					if ( ! control.invalidDate ) {
 						control.populateDateInputs();
 					}
 				} ) );
 			} );
 
 			control.inputElements.month.bind( control.updateDaysForMonth );
 			control.inputElements.year.bind( control.updateDaysForMonth );
 			control.populateDateInputs();
 			control.setting.bind( control.populateDateInputs );
 
 			// Start populating setting after inputs have been populated.
 			_.each( control.inputElements, function( element ) {
 				element.bind( control.populateSetting );
 			} );
 		},
 
 		/**
 		 * Parse datetime string.
 		 *
 		 * @since 4.9.0
 		 *
 		 * @param {string} datetime - Date/Time string. Accepts Y-m-d[ H:i[:s]] format.
 		 * @return {Object|null} Returns object containing date components or null if parse error.
 		 */
 		parseDateTime: function parseDateTime( datetime ) {
 			var control = this, matches, date, midDayHour = 12;
 
 			if ( datetime ) {
 				matches = datetime.match( /^(\d\d\d\d)-(\d\d)-(\d\d)(?: (\d\d):(\d\d)(?::(\d\d))?)?$/ );
 			}
 
 			if ( ! matches ) {
 				return null;
 			}
 
 			matches.shift();
 
 			date = {
 				year: matches.shift(),
 				month: matches.shift(),
 				day: matches.shift(),
 				hour: matches.shift() || '00',
 				minute: matches.shift() || '00',
 				second: matches.shift() || '00'
 			};
 
 			if ( control.params.includeTime && control.params.twelveHourFormat ) {
 				date.hour = parseInt( date.hour, 10 );
 				date.meridian = date.hour >= midDayHour ? 'pm' : 'am';
 				date.hour = date.hour % midDayHour ? String( date.hour % midDayHour ) : String( midDayHour );
 				delete date.second; // @todo Why only if twelveHourFormat?
 			}
 
 			return date;
 		},
 
 		/**
 		 * Validates if input components have valid date and time.
 		 *
 		 * @since 4.9.0
 		 * @return {boolean} If date input fields has error.
 		 */
 		validateInputs: function validateInputs() {
 			var control = this, components, validityInput;
 
 			control.invalidDate = false;
 
 			components = [ 'year', 'day' ];
 			if ( control.params.includeTime ) {
 				components.push( 'hour', 'minute' );
 			}
 
 			_.find( components, function( component ) {
 				var element, max, min, value;
 
 				element = control.inputElements[ component ];
 				validityInput = element.element.get( 0 );
 				max = parseInt( element.element.attr( 'max' ), 10 );
 				min = parseInt( element.element.attr( 'min' ), 10 );
 				value = parseInt( element(), 10 );
 				control.invalidDate = isNaN( value ) || value > max || value < min;
 
 				if ( ! control.invalidDate ) {
 					validityInput.setCustomValidity( '' );
 				}
 
 				return control.invalidDate;
 			} );
 
 			if ( control.inputElements.meridian && ! control.invalidDate ) {
 				validityInput = control.inputElements.meridian.element.get( 0 );
 				if ( 'am' !== control.inputElements.meridian.get() && 'pm' !== control.inputElements.meridian.get() ) {
 					control.invalidDate = true;
 				} else {
 					validityInput.setCustomValidity( '' );
 				}
 			}
 
 			if ( control.invalidDate ) {
 				validityInput.setCustomValidity( api.l10n.invalidValue );
 			} else {
 				validityInput.setCustomValidity( '' );
 			}
 			if ( ! control.section() || api.section.has( control.section() ) && api.section( control.section() ).expanded() ) {
 				_.result( validityInput, 'reportValidity' );
 			}
 
 			return control.invalidDate;
 		},
 
 		/**
 		 * Updates number of days according to the month and year selected.
 		 *
 		 * @since 4.9.0
 		 * @return {void}
 		 */
 		updateDaysForMonth: function updateDaysForMonth() {
 			var control = this, daysInMonth, year, month, day;
 
 			month = parseInt( control.inputElements.month(), 10 );
 			year = parseInt( control.inputElements.year(), 10 );
 			day = parseInt( control.inputElements.day(), 10 );
 
 			if ( month && year ) {
 				daysInMonth = new Date( year, month, 0 ).getDate();
 				control.inputElements.day.element.attr( 'max', daysInMonth );
 
 				if ( day > daysInMonth ) {
 					control.inputElements.day( String( daysInMonth ) );
 				}
 			}
 		},
 
 		/**
 		 * Populate setting value from the inputs.
 		 *
 		 * @since 4.9.0
 		 * @return {boolean} If setting updated.
 		 */
 		populateSetting: function populateSetting() {
 			var control = this, date;
 
 			if ( control.validateInputs() || ! control.params.allowPastDate && ! control.isFutureDate() ) {
 				return false;
 			}
 
 			date = control.convertInputDateToString();
 			control.setting.set( date );
 			return true;
 		},
 
 		/**
 		 * Converts input values to string in Y-m-d H:i:s format.
 		 *
 		 * @since 4.9.0
 		 * @return {string} Date string.
 		 */
 		convertInputDateToString: function convertInputDateToString() {
 			var control = this, date = '', dateFormat, hourInTwentyFourHourFormat,
 				getElementValue, pad;
 
 			pad = function( number, padding ) {
 				var zeros;
 				if ( String( number ).length < padding ) {
 					zeros = padding - String( number ).length;
 					number = Math.pow( 10, zeros ).toString().substr( 1 ) + String( number );
 				}
 				return number;
 			};
 
 			getElementValue = function( component ) {
 				var value = parseInt( control.inputElements[ component ].get(), 10 );
 
 				if ( _.contains( [ 'month', 'day', 'hour', 'minute' ], component ) ) {
 					value = pad( value, 2 );
 				} else if ( 'year' === component ) {
 					value = pad( value, 4 );
 				}
 				return value;
 			};
 
 			dateFormat = [ 'year', '-', 'month', '-', 'day' ];
 			if ( control.params.includeTime ) {
 				hourInTwentyFourHourFormat = control.inputElements.meridian ? control.convertHourToTwentyFourHourFormat( control.inputElements.hour(), control.inputElements.meridian() ) : control.inputElements.hour();
 				dateFormat = dateFormat.concat( [ ' ', pad( hourInTwentyFourHourFormat, 2 ), ':', 'minute', ':', '00' ] );
 			}
 
 			_.each( dateFormat, function( component ) {
 				date += control.inputElements[ component ] ? getElementValue( component ) : component;
 			} );
 
 			return date;
 		},
 
 		/**
 		 * Check if the date is in the future.
 		 *
 		 * @since 4.9.0
 		 * @return {boolean} True if future date.
 		 */
 		isFutureDate: function isFutureDate() {
 			var control = this;
 			return 0 < api.utils.getRemainingTime( control.convertInputDateToString() );
 		},
 
 		/**
 		 * Convert hour in twelve hour format to twenty four hour format.
 		 *
 		 * @since 4.9.0
 		 * @param {string} hourInTwelveHourFormat - Hour in twelve hour format.
 		 * @param {string} meridian - Either 'am' or 'pm'.
 		 * @return {string} Hour in twenty four hour format.
 		 */
 		convertHourToTwentyFourHourFormat: function convertHour( hourInTwelveHourFormat, meridian ) {
 			var hourInTwentyFourHourFormat, hour, midDayHour = 12;
 
 			hour = parseInt( hourInTwelveHourFormat, 10 );
 			if ( isNaN( hour ) ) {
 				return '';
 			}
 
 			if ( 'pm' === meridian && hour < midDayHour ) {
 				hourInTwentyFourHourFormat = hour + midDayHour;
 			} else if ( 'am' === meridian && midDayHour === hour ) {
 				hourInTwentyFourHourFormat = hour - midDayHour;
 			} else {
 				hourInTwentyFourHourFormat = hour;
 			}
 
 			return String( hourInTwentyFourHourFormat );
 		},
 
 		/**
 		 * Populates date inputs in date fields.
 		 *
 		 * @since 4.9.0
 		 * @return {boolean} Whether the inputs were populated.
 		 */
 		populateDateInputs: function populateDateInputs() {
 			var control = this, parsed;
 
 			parsed = control.parseDateTime( control.setting.get() );
 
 			if ( ! parsed ) {
 				return false;
 			}
 
 			_.each( control.inputElements, function( element, component ) {
 				var value = parsed[ component ]; // This will be zero-padded string.
 
 				// Set month and meridian regardless of focused state since they are dropdowns.
 				if ( 'month' === component || 'meridian' === component ) {
 
 					// Options in dropdowns are not zero-padded.
 					value = value.replace( /^0/, '' );
 
 					element.set( value );
 				} else {
 
 					value = parseInt( value, 10 );
 					if ( ! element.element.is( document.activeElement ) ) {
 
 						// Populate element with zero-padded value if not focused.
 						element.set( parsed[ component ] );
 					} else if ( value !== parseInt( element(), 10 ) ) {
 
 						// Forcibly update the value if its underlying value changed, regardless of zero-padding.
 						element.set( String( value ) );
 					}
 				}
 			} );
 
 			return true;
 		},
 
 		/**
 		 * Toggle future date notification for date control.
 		 *
 		 * @since 4.9.0
 		 * @param {boolean} notify Add or remove the notification.
 		 * @return {wp.customize.DateTimeControl}
 		 */
 		toggleFutureDateNotification: function toggleFutureDateNotification( notify ) {
 			var control = this, notificationCode, notification;
 
 			notificationCode = 'not_future_date';
 
 			if ( notify ) {
 				notification = new api.Notification( notificationCode, {
 					type: 'error',
 					message: api.l10n.futureDateError
 				} );
 				control.notifications.add( notification );
 			} else {
 				control.notifications.remove( notificationCode );
 			}
 
 			return control;
 		}
 	});
 
 	/**
 	 * Class PreviewLinkControl.
 	 *
 	 * @since 4.9.0
 	 * @class    wp.customize.PreviewLinkControl
 	 * @augments wp.customize.Control
 	 */
 	api.PreviewLinkControl = api.Control.extend(/** @lends wp.customize.PreviewLinkControl.prototype */{
 
 		defaults: _.extend( {}, api.Control.prototype.defaults, {
 			templateId: 'customize-preview-link-control'
 		} ),
 
 		/**
 		 * Initialize behaviors.
 		 *
 		 * @since 4.9.0
 		 * @return {void}
 		 */
 		ready: function ready() {
 			var control = this, element, component, node, url, input, button;
 
 			_.bindAll( control, 'updatePreviewLink' );
 
 			if ( ! control.setting ) {
 			    control.setting = new api.Value();
 			}
 
 			control.previewElements = {};
 
 			control.container.find( '.preview-control-element' ).each( function() {
 				node = $( this );
 				component = node.data( 'component' );
 				element = new api.Element( node );
 				control.previewElements[ component ] = element;
 				control.elements.push( element );
 			} );
 
 			url = control.previewElements.url;
 			input = control.previewElements.input;
 			button = control.previewElements.button;
 
 			input.link( control.setting );
 			url.link( control.setting );
 
 			url.bind( function( value ) {
 				url.element.parent().attr( {
 					href: value,
 					target: api.settings.changeset.uuid
 				} );
 			} );
 
 			api.bind( 'ready', control.updatePreviewLink );
 			api.state( 'saved' ).bind( control.updatePreviewLink );
 			api.state( 'changesetStatus' ).bind( control.updatePreviewLink );
 			api.state( 'activated' ).bind( control.updatePreviewLink );
 			api.previewer.previewUrl.bind( control.updatePreviewLink );
 
 			button.element.on( 'click', function( event ) {
 				event.preventDefault();
 				if ( control.setting() ) {
 					input.element.select();
 					document.execCommand( 'copy' );
 					button( button.element.data( 'copied-text' ) );
 				}
 			} );
 
 			url.element.parent().on( 'click', function( event ) {
 				if ( $( this ).hasClass( 'disabled' ) ) {
 					event.preventDefault();
 				}
 			} );
 
 			button.element.on( 'mouseenter', function() {
 				if ( control.setting() ) {
 					button( button.element.data( 'copy-text' ) );
 				}
 			} );
 		},
 
 		/**
 		 * Updates Preview Link
 		 *
 		 * @since 4.9.0
 		 * @return {void}
 		 */
 		updatePreviewLink: function updatePreviewLink() {
 			var control = this, unsavedDirtyValues;
 
 			unsavedDirtyValues = ! api.state( 'saved' ).get() || '' === api.state( 'changesetStatus' ).get() || 'auto-draft' === api.state( 'changesetStatus' ).get();
 
 			control.toggleSaveNotification( unsavedDirtyValues );
 			control.previewElements.url.element.parent().toggleClass( 'disabled', unsavedDirtyValues );
 			control.previewElements.button.element.prop( 'disabled', unsavedDirtyValues );
 			control.setting.set( api.previewer.getFrontendPreviewUrl() );
 		},
 
 		/**
 		 * Toggles save notification.
 		 *
 		 * @since 4.9.0
 		 * @param {boolean} notify Add or remove notification.
 		 * @return {void}
 		 */
 		toggleSaveNotification: function toggleSaveNotification( notify ) {
 			var control = this, notificationCode, notification;
 
 			notificationCode = 'changes_not_saved';
 
 			if ( notify ) {
 				notification = new api.Notification( notificationCode, {
 					type: 'info',
 					message: api.l10n.saveBeforeShare
 				} );
 				control.notifications.add( notification );
 			} else {
 				control.notifications.remove( notificationCode );
 			}
 		}
 	});
 
 	/**
 	 * Change objects contained within the main customize object to Settings.
 	 *
 	 * @alias wp.customize.defaultConstructor
 	 */
 	api.defaultConstructor = api.Setting;
 
 	/**
 	 * Callback for resolved controls.
 	 *
 	 * @callback wp.customize.deferredControlsCallback
 	 * @param {wp.customize.Control[]} controls Resolved controls.
 	 */
 
 	/**
 	 * Collection of all registered controls.
 	 *
 	 * @alias wp.customize.control
 	 *
 	 * @since 3.4.0
 	 *
 	 * @type {Function}
 	 * @param {...string} ids - One or more ids for controls to obtain.
 	 * @param {deferredControlsCallback} [callback] - Function called when all supplied controls exist.
 	 * @return {wp.customize.Control|undefined|jQuery.promise} Control instance or undefined (if function called with one id param),
 	 *                                                         or promise resolving to requested controls.
 	 *
 	 * @example <caption>Loop over all registered controls.</caption>
 	 * wp.customize.control.each( function( control ) { ... } );
 	 *
 	 * @example <caption>Getting `background_color` control instance.</caption>
 	 * control = wp.customize.control( 'background_color' );
 	 *
 	 * @example <caption>Check if control exists.</caption>
 	 * hasControl = wp.customize.control.has( 'background_color' );
 	 *
 	 * @example <caption>Deferred getting of `background_color` control until it exists, using callback.</caption>
 	 * wp.customize.control( 'background_color', function( control ) { ... } );
 	 *
 	 * @example <caption>Get title and tagline controls when they both exist, using promise (only available when multiple IDs are present).</caption>
 	 * promise = wp.customize.control( 'blogname', 'blogdescription' );
 	 * promise.done( function( titleControl, taglineControl ) { ... } );
 	 *
 	 * @example <caption>Get title and tagline controls when they both exist, using callback.</caption>
 	 * wp.customize.control( 'blogname', 'blogdescription', function( titleControl, taglineControl ) { ... } );
 	 *
 	 * @example <caption>Getting setting value for `background_color` control.</caption>
 	 * value = wp.customize.control( 'background_color ').setting.get();
 	 * value = wp.customize( 'background_color' ).get(); // Same as above, since setting ID and control ID are the same.
 	 *
 	 * @example <caption>Add new control for site title.</caption>
 	 * wp.customize.control.add( new wp.customize.Control( 'other_blogname', {
 	 *     setting: 'blogname',
 	 *     type: 'text',
 	 *     label: 'Site title',
 	 *     section: 'other_site_identify'
 	 * } ) );
 	 *
 	 * @example <caption>Remove control.</caption>
 	 * wp.customize.control.remove( 'other_blogname' );
 	 *
 	 * @example <caption>Listen for control being added.</caption>
 	 * wp.customize.control.bind( 'add', function( addedControl ) { ... } )
 	 *
 	 * @example <caption>Listen for control being removed.</caption>
 	 * wp.customize.control.bind( 'removed', function( removedControl ) { ... } )
 	 */
 	api.control = new api.Values({ defaultConstructor: api.Control });
 
 	/**
 	 * Callback for resolved sections.
 	 *
 	 * @callback wp.customize.deferredSectionsCallback
 	 * @param {wp.customize.Section[]} sections Resolved sections.
 	 */
 
 	/**
 	 * Collection of all registered sections.
 	 *
 	 * @alias wp.customize.section
 	 *
 	 * @since 3.4.0
 	 *
 	 * @type {Function}
 	 * @param {...string} ids - One or more ids for sections to obtain.
 	 * @param {deferredSectionsCallback} [callback] - Function called when all supplied sections exist.
 	 * @return {wp.customize.Section|undefined|jQuery.promise} Section instance or undefined (if function called with one id param),
 	 *                                                         or promise resolving to requested sections.
 	 *
 	 * @example <caption>Loop over all registered sections.</caption>
 	 * wp.customize.section.each( function( section ) { ... } )
 	 *
 	 * @example <caption>Getting `title_tagline` section instance.</caption>
 	 * section = wp.customize.section( 'title_tagline' )
 	 *
 	 * @example <caption>Expand dynamically-created section when it exists.</caption>
 	 * wp.customize.section( 'dynamically_created', function( section ) {
 	 *     section.expand();
 	 * } );
 	 *
 	 * @see {@link wp.customize.control} for further examples of how to interact with {@link wp.customize.Values} instances.
 	 */
 	api.section = new api.Values({ defaultConstructor: api.Section });
 
 	/**
 	 * Callback for resolved panels.
 	 *
 	 * @callback wp.customize.deferredPanelsCallback
 	 * @param {wp.customize.Panel[]} panels Resolved panels.
 	 */
 
 	/**
 	 * Collection of all registered panels.
 	 *
 	 * @alias wp.customize.panel
 	 *
 	 * @since 4.0.0
 	 *
 	 * @type {Function}
 	 * @param {...string} ids - One or more ids for panels to obtain.
 	 * @param {deferredPanelsCallback} [callback] - Function called when all supplied panels exist.
 	 * @return {wp.customize.Panel|undefined|jQuery.promise} Panel instance or undefined (if function called with one id param),
 	 *                                                       or promise resolving to requested panels.
 	 *
 	 * @example <caption>Loop over all registered panels.</caption>
 	 * wp.customize.panel.each( function( panel ) { ... } )
 	 *
 	 * @example <caption>Getting nav_menus panel instance.</caption>
 	 * panel = wp.customize.panel( 'nav_menus' );
 	 *
 	 * @example <caption>Expand dynamically-created panel when it exists.</caption>
 	 * wp.customize.panel( 'dynamically_created', function( panel ) {
 	 *     panel.expand();
 	 * } );
 	 *
 	 * @see {@link wp.customize.control} for further examples of how to interact with {@link wp.customize.Values} instances.
 	 */
 	api.panel = new api.Values({ defaultConstructor: api.Panel });
 
 	/**
 	 * Callback for resolved notifications.
 	 *
 	 * @callback wp.customize.deferredNotificationsCallback
 	 * @param {wp.customize.Notification[]} notifications Resolved notifications.
 	 */
 
 	/**
 	 * Collection of all global notifications.
 	 *
 	 * @alias wp.customize.notifications
 	 *
 	 * @since 4.9.0
 	 *
 	 * @type {Function}
 	 * @param {...string} codes - One or more codes for notifications to obtain.
 	 * @param {deferredNotificationsCallback} [callback] - Function called when all supplied notifications exist.
 	 * @return {wp.customize.Notification|undefined|jQuery.promise} Notification instance or undefined (if function called with one code param),
 	 *                                                              or promise resolving to requested notifications.
 	 *
 	 * @example <caption>Check if existing notification</caption>
 	 * exists = wp.customize.notifications.has( 'a_new_day_arrived' );
 	 *
 	 * @example <caption>Obtain existing notification</caption>
 	 * notification = wp.customize.notifications( 'a_new_day_arrived' );
 	 *
 	 * @example <caption>Obtain notification that may not exist yet.</caption>
 	 * wp.customize.notifications( 'a_new_day_arrived', function( notification ) { ... } );
 	 *
 	 * @example <caption>Add a warning notification.</caption>
 	 * wp.customize.notifications.add( new wp.customize.Notification( 'midnight_almost_here', {
 	 *     type: 'warning',
 	 *     message: 'Midnight has almost arrived!',
 	 *     dismissible: true
 	 * } ) );
 	 *
 	 * @example <caption>Remove a notification.</caption>
 	 * wp.customize.notifications.remove( 'a_new_day_arrived' );
 	 *
 	 * @see {@link wp.customize.control} for further examples of how to interact with {@link wp.customize.Values} instances.
 	 */
 	api.notifications = new api.Notifications();
 
 	api.PreviewFrame = api.Messenger.extend(/** @lends wp.customize.PreviewFrame.prototype */{
 		sensitivity: null, // Will get set to api.settings.timeouts.previewFrameSensitivity.
 
 		/**
 		 * An object that fetches a preview in the background of the document, which
 		 * allows for seamless replacement of an existing preview.
 		 *
 		 * @constructs wp.customize.PreviewFrame
 		 * @augments   wp.customize.Messenger
 		 *
 		 * @param {Object} params.container
 		 * @param {Object} params.previewUrl
 		 * @param {Object} params.query
 		 * @param {Object} options
 		 */
 		initialize: function( params, options ) {
 			var deferred = $.Deferred();
 
 			/*
 			 * Make the instance of the PreviewFrame the promise object
 			 * so other objects can easily interact with it.
 			 */
 			deferred.promise( this );
 
 			this.container = params.container;
 
 			$.extend( params, { channel: api.PreviewFrame.uuid() });
 
 			api.Messenger.prototype.initialize.call( this, params, options );
 
 			this.add( 'previewUrl', params.previewUrl );
 
 			this.query = $.extend( params.query || {}, { customize_messenger_channel: this.channel() });
 
 			this.run( deferred );
 		},
 
 		/**
 		 * Run the preview request.
 		 *
 		 * @param {Object} deferred jQuery Deferred object to be resolved with
 		 *                          the request.
 		 */
 		run: function( deferred ) {
 			var previewFrame = this,
 				loaded = false,
 				ready = false,
 				readyData = null,
 				hasPendingChangesetUpdate = '{}' !== previewFrame.query.customized,
 				urlParser,
 				params,
 				form;
 
 			if ( previewFrame._ready ) {
 				previewFrame.unbind( 'ready', previewFrame._ready );
 			}
 
 			previewFrame._ready = function( data ) {
 				ready = true;
 				readyData = data;
 				previewFrame.container.addClass( 'iframe-ready' );
 				if ( ! data ) {
 					return;
 				}
 
 				if ( loaded ) {
 					deferred.resolveWith( previewFrame, [ data ] );
 				}
 			};
 
 			previewFrame.bind( 'ready', previewFrame._ready );
 
 			urlParser = document.createElement( 'a' );
 			urlParser.href = previewFrame.previewUrl();
 
 			params = _.extend(
 				api.utils.parseQueryString( urlParser.search.substr( 1 ) ),
 				{
 					customize_changeset_uuid: previewFrame.query.customize_changeset_uuid,
 					customize_theme: previewFrame.query.customize_theme,
 					customize_messenger_channel: previewFrame.query.customize_messenger_channel
 				}
 			);
 			if ( api.settings.changeset.autosaved || ! api.state( 'saved' ).get() ) {
 				params.customize_autosaved = 'on';
 			}
 
 			urlParser.search = $.param( params );
 			previewFrame.iframe = $( '<iframe />', {
 				title: api.l10n.previewIframeTitle,
 				name: 'customize-' + previewFrame.channel()
 			} );
 			previewFrame.iframe.attr( 'onmousewheel', '' ); // Workaround for Safari bug. See WP Trac #38149.
 			previewFrame.iframe.attr( 'sandbox', 'allow-forms allow-modals allow-orientation-lock allow-pointer-lock allow-popups allow-popups-to-escape-sandbox allow-presentation allow-same-origin allow-scripts' );
 
 			if ( ! hasPendingChangesetUpdate ) {
 				previewFrame.iframe.attr( 'src', urlParser.href );
 			} else {
 				previewFrame.iframe.attr( 'data-src', urlParser.href ); // For debugging purposes.
 			}
 
 			previewFrame.iframe.appendTo( previewFrame.container );
 			previewFrame.targetWindow( previewFrame.iframe[0].contentWindow );
 
 			/*
 			 * Submit customized data in POST request to preview frame window since
 			 * there are setting value changes not yet written to changeset.
 			 */
 			if ( hasPendingChangesetUpdate ) {
 				form = $( '<form>', {
 					action: urlParser.href,
 					target: previewFrame.iframe.attr( 'name' ),
 					method: 'post',
 					hidden: 'hidden'
 				} );
 				form.append( $( '<input>', {
 					type: 'hidden',
 					name: '_method',
 					value: 'GET'
 				} ) );
 				_.each( previewFrame.query, function( value, key ) {
 					form.append( $( '<input>', {
 						type: 'hidden',
 						name: key,
 						value: value
 					} ) );
 				} );
 				previewFrame.container.append( form );
 				form.trigger( 'submit' );
 				form.remove(); // No need to keep the form around after submitted.
 			}
 
 			previewFrame.bind( 'iframe-loading-error', function( error ) {
 				previewFrame.iframe.remove();
 
 				// Check if the user is not logged in.
 				if ( 0 === error ) {
 					previewFrame.login( deferred );
 					return;
 				}
 
 				// Check for cheaters.
 				if ( -1 === error ) {
 					deferred.rejectWith( previewFrame, [ 'cheatin' ] );
 					return;
 				}
 
 				deferred.rejectWith( previewFrame, [ 'request failure' ] );
 			} );
 
 			previewFrame.iframe.one( 'load', function() {
 				loaded = true;
 
 				if ( ready ) {
 					deferred.resolveWith( previewFrame, [ readyData ] );
 				} else {
 					setTimeout( function() {
 						deferred.rejectWith( previewFrame, [ 'ready timeout' ] );
 					}, previewFrame.sensitivity );
 				}
 			});
 		},
 
 		login: function( deferred ) {
 			var self = this,
 				reject;
 
 			reject = function() {
 				deferred.rejectWith( self, [ 'logged out' ] );
 			};
 
 			if ( this.triedLogin ) {
 				return reject();
 			}
 
 			// Check if we have an admin cookie.
 			$.get( api.settings.url.ajax, {
 				action: 'logged-in'
 			}).fail( reject ).done( function( response ) {
 				var iframe;
 
 				if ( '1' !== response ) {
 					reject();
 				}
 
 				iframe = $( '<iframe />', { 'src': self.previewUrl(), 'title': api.l10n.previewIframeTitle } ).hide();
 				iframe.appendTo( self.container );
 				iframe.on( 'load', function() {
 					self.triedLogin = true;
 
 					iframe.remove();
 					self.run( deferred );
 				});
 			});
 		},
 
 		destroy: function() {
 			api.Messenger.prototype.destroy.call( this );
 
 			if ( this.iframe ) {
 				this.iframe.remove();
 			}
 
 			delete this.iframe;
 			delete this.targetWindow;
 		}
 	});
 
 	(function(){
 		var id = 0;
 		/**
 		 * Return an incremented ID for a preview messenger channel.
 		 *
 		 * This function is named "uuid" for historical reasons, but it is a
 		 * misnomer as it is not an actual UUID, and it is not universally unique.
 		 * This is not to be confused with `api.settings.changeset.uuid`.
 		 *
 		 * @return {string}
 		 */
 		api.PreviewFrame.uuid = function() {
 			return 'preview-' + String( id++ );
 		};
 	}());
 
 	/**
 	 * Set the document title of the customizer.
 	 *
 	 * @alias wp.customize.setDocumentTitle
 	 *
 	 * @since 4.1.0
 	 *
 	 * @param {string} documentTitle
 	 */
 	api.setDocumentTitle = function ( documentTitle ) {
 		var tmpl, title;
 		tmpl = api.settings.documentTitleTmpl;
 		title = tmpl.replace( '%s', documentTitle );
 		document.title = title;
 		api.trigger( 'title', title );
 	};
 
 	api.Previewer = api.Messenger.extend(/** @lends wp.customize.Previewer.prototype */{
 		refreshBuffer: null, // Will get set to api.settings.timeouts.windowRefresh.
 
 		/**
 		 * @constructs wp.customize.Previewer
 		 * @augments   wp.customize.Messenger
 		 *
 		 * @param {Array}  params.allowedUrls
 		 * @param {string} params.container   A selector or jQuery element for the preview
 		 *                                    frame to be placed.
 		 * @param {string} params.form
 		 * @param {string} params.previewUrl  The URL to preview.
 		 * @param {Object} options
 		 */
 		initialize: function( params, options ) {
 			var previewer = this,
 				urlParser = document.createElement( 'a' );
 
 			$.extend( previewer, options || {} );
 			previewer.deferred = {
 				active: $.Deferred()
 			};
 
 			// Debounce to prevent hammering server and then wait for any pending update requests.
 			previewer.refresh = _.debounce(
 				( function( originalRefresh ) {
 					return function() {
 						var isProcessingComplete, refreshOnceProcessingComplete;
 						isProcessingComplete = function() {
 							return 0 === api.state( 'processing' ).get();
 						};
 						if ( isProcessingComplete() ) {
 							originalRefresh.call( previewer );
 						} else {
 							refreshOnceProcessingComplete = function() {
 								if ( isProcessingComplete() ) {
 									originalRefresh.call( previewer );
 									api.state( 'processing' ).unbind( refreshOnceProcessingComplete );
 								}
 							};
 							api.state( 'processing' ).bind( refreshOnceProcessingComplete );
 						}
 					};
 				}( previewer.refresh ) ),
 				previewer.refreshBuffer
 			);
 
 			previewer.container   = api.ensure( params.container );
 			previewer.allowedUrls = params.allowedUrls;
 
 			params.url = window.location.href;
 
 			api.Messenger.prototype.initialize.call( previewer, params );
 
 			urlParser.href = previewer.origin();
 			previewer.add( 'scheme', urlParser.protocol.replace( /:$/, '' ) );
 
 			/*
 			 * Limit the URL to internal, front-end links.
 			 *
 			 * If the front end and the admin are served from the same domain, load the
 			 * preview over ssl if the Customizer is being loaded over ssl. This avoids
 			 * insecure content warnings. This is not attempted if the admin and front end
 			 * are on different domains to avoid the case where the front end doesn't have
 			 * ssl certs.
 			 */
 
 			previewer.add( 'previewUrl', params.previewUrl ).setter( function( to ) {
 				var result = null, urlParser, queryParams, parsedAllowedUrl, parsedCandidateUrls = [];
 				urlParser = document.createElement( 'a' );
 				urlParser.href = to;
 
 				// Abort if URL is for admin or (static) files in wp-includes or wp-content.
 				if ( /\/wp-(admin|includes|content)(\/|$)/.test( urlParser.pathname ) ) {
 					return null;
 				}
 
 				// Remove state query params.
 				if ( urlParser.search.length > 1 ) {
 					queryParams = api.utils.parseQueryString( urlParser.search.substr( 1 ) );
 					delete queryParams.customize_changeset_uuid;
 					delete queryParams.customize_theme;
 					delete queryParams.customize_messenger_channel;
 					delete queryParams.customize_autosaved;
 					if ( _.isEmpty( queryParams ) ) {
 						urlParser.search = '';
 					} else {
 						urlParser.search = $.param( queryParams );
 					}
 				}
 
 				parsedCandidateUrls.push( urlParser );
 
 				// Prepend list with URL that matches the scheme/protocol of the iframe.
 				if ( previewer.scheme.get() + ':' !== urlParser.protocol ) {
 					urlParser = document.createElement( 'a' );
 					urlParser.href = parsedCandidateUrls[0].href;
 					urlParser.protocol = previewer.scheme.get() + ':';
 					parsedCandidateUrls.unshift( urlParser );
 				}
 
 				// Attempt to match the URL to the control frame's scheme and check if it's allowed. If not, try the original URL.
 				parsedAllowedUrl = document.createElement( 'a' );
 				_.find( parsedCandidateUrls, function( parsedCandidateUrl ) {
 					return ! _.isUndefined( _.find( previewer.allowedUrls, function( allowedUrl ) {
 						parsedAllowedUrl.href = allowedUrl;
 						if ( urlParser.protocol === parsedAllowedUrl.protocol && urlParser.host === parsedAllowedUrl.host && 0 === urlParser.pathname.indexOf( parsedAllowedUrl.pathname.replace( /\/$/, '' ) ) ) {
 							result = parsedCandidateUrl.href;
 							return true;
 						}
 					} ) );
 				} );
 
 				return result;
 			});
 
 			previewer.bind( 'ready', previewer.ready );
 
 			// Start listening for keep-alive messages when iframe first loads.
 			previewer.deferred.active.done( _.bind( previewer.keepPreviewAlive, previewer ) );
 
 			previewer.bind( 'synced', function() {
 				previewer.send( 'active' );
 			} );
 
 			// Refresh the preview when the URL is changed (but not yet).
 			previewer.previewUrl.bind( previewer.refresh );
 
 			previewer.scroll = 0;
 			previewer.bind( 'scroll', function( distance ) {
 				previewer.scroll = distance;
 			});
 
 			// Update the URL when the iframe sends a URL message, resetting scroll position. If URL is unchanged, then refresh.
 			previewer.bind( 'url', function( url ) {
 				var onUrlChange, urlChanged = false;
 				previewer.scroll = 0;
 				onUrlChange = function() {
 					urlChanged = true;
 				};
 				previewer.previewUrl.bind( onUrlChange );
 				previewer.previewUrl.set( url );
 				previewer.previewUrl.unbind( onUrlChange );
 				if ( ! urlChanged ) {
 					previewer.refresh();
 				}
 			} );
 
 			// Update the document title when the preview changes.
 			previewer.bind( 'documentTitle', function ( title ) {
 				api.setDocumentTitle( title );
 			} );
 		},
 
 		/**
 		 * Handle the preview receiving the ready message.
 		 *
 		 * @since 4.7.0
 		 * @access public
 		 *
 		 * @param {Object} data - Data from preview.
 		 * @param {string} data.currentUrl - Current URL.
 		 * @param {Object} data.activePanels - Active panels.
 		 * @param {Object} data.activeSections Active sections.
 		 * @param {Object} data.activeControls Active controls.
 		 * @return {void}
 		 */
 		ready: function( data ) {
 			var previewer = this, synced = {}, constructs;
 
 			synced.settings = api.get();
 			synced['settings-modified-while-loading'] = previewer.settingsModifiedWhileLoading;
 			if ( 'resolved' !== previewer.deferred.active.state() || previewer.loading ) {
 				synced.scroll = previewer.scroll;
 			}
 			synced['edit-shortcut-visibility'] = api.state( 'editShortcutVisibility' ).get();
 			previewer.send( 'sync', synced );
 
 			// Set the previewUrl without causing the url to set the iframe.
 			if ( data.currentUrl ) {
 				previewer.previewUrl.unbind( previewer.refresh );
 				previewer.previewUrl.set( data.currentUrl );
 				previewer.previewUrl.bind( previewer.refresh );
 			}
 
 			/*
 			 * Walk over all panels, sections, and controls and set their
 			 * respective active states to true if the preview explicitly
 			 * indicates as such.
 			 */
 			constructs = {
 				panel: data.activePanels,
 				section: data.activeSections,
 				control: data.activeControls
 			};
 			_( constructs ).each( function ( activeConstructs, type ) {
 				api[ type ].each( function ( construct, id ) {
 					var isDynamicallyCreated = _.isUndefined( api.settings[ type + 's' ][ id ] );
 
 					/*
 					 * If the construct was created statically in PHP (not dynamically in JS)
 					 * then consider a missing (undefined) value in the activeConstructs to
 					 * mean it should be deactivated (since it is gone). But if it is
 					 * dynamically created then only toggle activation if the value is defined,
 					 * as this means that the construct was also then correspondingly
 					 * created statically in PHP and the active callback is available.
 					 * Otherwise, dynamically-created constructs should normally have
 					 * their active states toggled in JS rather than from PHP.
 					 */
 					if ( ! isDynamicallyCreated || ! _.isUndefined( activeConstructs[ id ] ) ) {
 						if ( activeConstructs[ id ] ) {
 							construct.activate();
 						} else {
 							construct.deactivate();
 						}
 					}
 				} );
 			} );
 
 			if ( data.settingValidities ) {
 				api._handleSettingValidities( {
 					settingValidities: data.settingValidities,
 					focusInvalidControl: false
 				} );
 			}
 		},
 
 		/**
 		 * Keep the preview alive by listening for ready and keep-alive messages.
 		 *
 		 * If a message is not received in the allotted time then the iframe will be set back to the last known valid URL.
 		 *
 		 * @since 4.7.0
 		 * @access public
 		 *
 		 * @return {void}
 		 */
 		keepPreviewAlive: function keepPreviewAlive() {
 			var previewer = this, keepAliveTick, timeoutId, handleMissingKeepAlive, scheduleKeepAliveCheck;
 
 			/**
 			 * Schedule a preview keep-alive check.
 			 *
 			 * Note that if a page load takes longer than keepAliveCheck milliseconds,
 			 * the keep-alive messages will still be getting sent from the previous
 			 * URL.
 			 */
 			scheduleKeepAliveCheck = function() {
 				timeoutId = setTimeout( handleMissingKeepAlive, api.settings.timeouts.keepAliveCheck );
 			};
 
 			/**
 			 * Set the previewerAlive state to true when receiving a message from the preview.
 			 */
 			keepAliveTick = function() {
 				api.state( 'previewerAlive' ).set( true );
 				clearTimeout( timeoutId );
 				scheduleKeepAliveCheck();
 			};
 
 			/**
 			 * Set the previewerAlive state to false if keepAliveCheck milliseconds have transpired without a message.
 			 *
 			 * This is most likely to happen in the case of a connectivity error, or if the theme causes the browser
 			 * to navigate to a non-allowed URL. Setting this state to false will force settings with a postMessage
 			 * transport to use refresh instead, causing the preview frame also to be replaced with the current
 			 * allowed preview URL.
 			 */
 			handleMissingKeepAlive = function() {
 				api.state( 'previewerAlive' ).set( false );
 			};
 			scheduleKeepAliveCheck();
 
 			previewer.bind( 'ready', keepAliveTick );
 			previewer.bind( 'keep-alive', keepAliveTick );
 		},
 
 		/**
 		 * Query string data sent with each preview request.
 		 *
 		 * @abstract
 		 */
 		query: function() {},
 
 		abort: function() {
 			if ( this.loading ) {
 				this.loading.destroy();
 				delete this.loading;
 			}
 		},
 
 		/**
 		 * Refresh the preview seamlessly.
 		 *
 		 * @since 3.4.0
 		 * @access public
 		 *
 		 * @return {void}
 		 */
 		refresh: function() {
 			var previewer = this, onSettingChange;
 
 			// Display loading indicator.
 			previewer.send( 'loading-initiated' );
 
 			previewer.abort();
 
 			previewer.loading = new api.PreviewFrame({
 				url:        previewer.url(),
 				previewUrl: previewer.previewUrl(),
 				query:      previewer.query( { excludeCustomizedSaved: true } ) || {},
 				container:  previewer.container
 			});
 
 			previewer.settingsModifiedWhileLoading = {};
 			onSettingChange = function( setting ) {
 				previewer.settingsModifiedWhileLoading[ setting.id ] = true;
 			};
 			api.bind( 'change', onSettingChange );
 			previewer.loading.always( function() {
 				api.unbind( 'change', onSettingChange );
 			} );
 
 			previewer.loading.done( function( readyData ) {
 				var loadingFrame = this, onceSynced;
 
 				previewer.preview = loadingFrame;
 				previewer.targetWindow( loadingFrame.targetWindow() );
 				previewer.channel( loadingFrame.channel() );
 
 				onceSynced = function() {
 					loadingFrame.unbind( 'synced', onceSynced );
 					if ( previewer._previousPreview ) {
 						previewer._previousPreview.destroy();
 					}
 					previewer._previousPreview = previewer.preview;
 					previewer.deferred.active.resolve();
 					delete previewer.loading;
 				};
 				loadingFrame.bind( 'synced', onceSynced );
 
 				// This event will be received directly by the previewer in normal navigation; this is only needed for seamless refresh.
 				previewer.trigger( 'ready', readyData );
 			});
 
 			previewer.loading.fail( function( reason ) {
 				previewer.send( 'loading-failed' );
 
 				if ( 'logged out' === reason ) {
 					if ( previewer.preview ) {
 						previewer.preview.destroy();
 						delete previewer.preview;
 					}
 
 					previewer.login().done( previewer.refresh );
 				}
 
 				if ( 'cheatin' === reason ) {
 					previewer.cheatin();
 				}
 			});
 		},
 
 		login: function() {
 			var previewer = this,
 				deferred, messenger, iframe;
 
 			if ( this._login ) {
 				return this._login;
 			}
 
 			deferred = $.Deferred();
 			this._login = deferred.promise();
 
 			messenger = new api.Messenger({
 				channel: 'login',
 				url:     api.settings.url.login
 			});
 
 			iframe = $( '<iframe />', { 'src': api.settings.url.login, 'title': api.l10n.loginIframeTitle } ).appendTo( this.container );
 
 			messenger.targetWindow( iframe[0].contentWindow );
 
 			messenger.bind( 'login', function () {
 				var refreshNonces = previewer.refreshNonces();
 
 				refreshNonces.always( function() {
 					iframe.remove();
 					messenger.destroy();
 					delete previewer._login;
 				});
 
 				refreshNonces.done( function() {
 					deferred.resolve();
 				});
 
 				refreshNonces.fail( function() {
 					previewer.cheatin();
 					deferred.reject();
 				});
 			});
 
 			return this._login;
 		},
 
 		cheatin: function() {
 			$( document.body ).empty().addClass( 'cheatin' ).append(
 				'<h1>' + api.l10n.notAllowedHeading + '</h1>' +
 				'<p>' + api.l10n.notAllowed + '</p>'
 			);
 		},
 
 		refreshNonces: function() {
 			var request, deferred = $.Deferred();
 
 			deferred.promise();
 
 			request = wp.ajax.post( 'customize_refresh_nonces', {
 				wp_customize: 'on',
 				customize_theme: api.settings.theme.stylesheet
 			});
 
 			request.done( function( response ) {
 				api.trigger( 'nonce-refresh', response );
 				deferred.resolve();
 			});
 
 			request.fail( function() {
 				deferred.reject();
 			});
 
 			return deferred;
 		}
 	});
 
 	api.settingConstructor = {};
 	api.controlConstructor = {
 		color:               api.ColorControl,
 		media:               api.MediaControl,
 		upload:              api.UploadControl,
 		image:               api.ImageControl,
 		cropped_image:       api.CroppedImageControl,
 		site_icon:           api.SiteIconControl,
 		header:              api.HeaderControl,
 		background:          api.BackgroundControl,
 		background_position: api.BackgroundPositionControl,
 		theme:               api.ThemeControl,
 		date_time:           api.DateTimeControl,
 		code_editor:         api.CodeEditorControl
 	};
 	api.panelConstructor = {
 		themes: api.ThemesPanel
 	};
 	api.sectionConstructor = {
 		themes: api.ThemesSection,
 		outer: api.OuterSection
 	};
 
 	/**
 	 * Handle setting_validities in an error response for the customize-save request.
 	 *
 	 * Add notifications to the settings and focus on the first control that has an invalid setting.
 	 *
 	 * @alias wp.customize._handleSettingValidities
 	 *
 	 * @since 4.6.0
 	 * @private
 	 *
 	 * @param {Object}  args
 	 * @param {Object}  args.settingValidities
 	 * @param {boolean} [args.focusInvalidControl=false]
 	 * @return {void}
 	 */
 	api._handleSettingValidities = function handleSettingValidities( args ) {
 		var invalidSettingControls, invalidSettings = [], wasFocused = false;
 
 		// Find the controls that correspond to each invalid setting.
 		_.each( args.settingValidities, function( validity, settingId ) {
 			var setting = api( settingId );
 			if ( setting ) {
 
 				// Add notifications for invalidities.
 				if ( _.isObject( validity ) ) {
 					_.each( validity, function( params, code ) {
 						var notification, existingNotification, needsReplacement = false;
 						notification = new api.Notification( code, _.extend( { fromServer: true }, params ) );
 
 						// Remove existing notification if already exists for code but differs in parameters.
 						existingNotification = setting.notifications( notification.code );
 						if ( existingNotification ) {
 							needsReplacement = notification.type !== existingNotification.type || notification.message !== existingNotification.message || ! _.isEqual( notification.data, existingNotification.data );
 						}
 						if ( needsReplacement ) {
 							setting.notifications.remove( code );
 						}
 
 						if ( ! setting.notifications.has( notification.code ) ) {
 							setting.notifications.add( notification );
 						}
 						invalidSettings.push( setting.id );
 					} );
 				}
 
 				// Remove notification errors that are no longer valid.
 				setting.notifications.each( function( notification ) {
 					if ( notification.fromServer && 'error' === notification.type && ( true === validity || ! validity[ notification.code ] ) ) {
 						setting.notifications.remove( notification.code );
 					}
 				} );
 			}
 		} );
 
 		if ( args.focusInvalidControl ) {
 			invalidSettingControls = api.findControlsForSettings( invalidSettings );
 
 			// Focus on the first control that is inside of an expanded section (one that is visible).
 			_( _.values( invalidSettingControls ) ).find( function( controls ) {
 				return _( controls ).find( function( control ) {
 					var isExpanded = control.section() && api.section.has( control.section() ) && api.section( control.section() ).expanded();
 					if ( isExpanded && control.expanded ) {
 						isExpanded = control.expanded();
 					}
 					if ( isExpanded ) {
 						control.focus();
 						wasFocused = true;
 					}
 					return wasFocused;
 				} );
 			} );
 
 			// Focus on the first invalid control.
 			if ( ! wasFocused && ! _.isEmpty( invalidSettingControls ) ) {
 				_.values( invalidSettingControls )[0][0].focus();
 			}
 		}
 	};
 
 	/**
 	 * Find all controls associated with the given settings.
 	 *
 	 * @alias wp.customize.findControlsForSettings
 	 *
 	 * @since 4.6.0
 	 * @param {string[]} settingIds Setting IDs.
 	 * @return {Object<string, wp.customize.Control>} Mapping setting ids to arrays of controls.
 	 */
 	api.findControlsForSettings = function findControlsForSettings( settingIds ) {
 		var controls = {}, settingControls;
 		_.each( _.unique( settingIds ), function( settingId ) {
 			var setting = api( settingId );
 			if ( setting ) {
 				settingControls = setting.findControls();
 				if ( settingControls && settingControls.length > 0 ) {
 					controls[ settingId ] = settingControls;
 				}
 			}
 		} );
 		return controls;
 	};
 
 	/**
 	 * Sort panels, sections, controls by priorities. Hide empty sections and panels.
 	 *
 	 * @alias wp.customize.reflowPaneContents
 	 *
 	 * @since 4.1.0
 	 */
 	api.reflowPaneContents = _.bind( function () {
 
 		var appendContainer, activeElement, rootHeadContainers, rootNodes = [], wasReflowed = false;
 
 		if ( document.activeElement ) {
 			activeElement = $( document.activeElement );
 		}
 
 		// Sort the sections within each panel.
 		api.panel.each( function ( panel ) {
 			if ( 'themes' === panel.id ) {
 				return; // Don't reflow theme sections, as doing so moves them after the themes container.
 			}
 
 			var sections = panel.sections(),
 				sectionHeadContainers = _.pluck( sections, 'headContainer' );
 			rootNodes.push( panel );
 			appendContainer = ( panel.contentContainer.is( 'ul' ) ) ? panel.contentContainer : panel.contentContainer.find( 'ul:first' );
 			if ( ! api.utils.areElementListsEqual( sectionHeadContainers, appendContainer.children( '[id]' ) ) ) {
 				_( sections ).each( function ( section ) {
 					appendContainer.append( section.headContainer );
 				} );
 				wasReflowed = true;
 			}
 		} );
 
 		// Sort the controls within each section.
 		api.section.each( function ( section ) {
 			var controls = section.controls(),
 				controlContainers = _.pluck( controls, 'container' );
 			if ( ! section.panel() ) {
 				rootNodes.push( section );
 			}
 			appendContainer = ( section.contentContainer.is( 'ul' ) ) ? section.contentContainer : section.contentContainer.find( 'ul:first' );
 			if ( ! api.utils.areElementListsEqual( controlContainers, appendContainer.children( '[id]' ) ) ) {
 				_( controls ).each( function ( control ) {
 					appendContainer.append( control.container );
 				} );
 				wasReflowed = true;
 			}
 		} );
 
 		// Sort the root panels and sections.
 		rootNodes.sort( api.utils.prioritySort );
 		rootHeadContainers = _.pluck( rootNodes, 'headContainer' );
 		appendContainer = $( '#customize-theme-controls .customize-pane-parent' ); // @todo This should be defined elsewhere, and to be configurable.
 		if ( ! api.utils.areElementListsEqual( rootHeadContainers, appendContainer.children() ) ) {
 			_( rootNodes ).each( function ( rootNode ) {
 				appendContainer.append( rootNode.headContainer );
 			} );
 			wasReflowed = true;
 		}
 
 		// Now re-trigger the active Value callbacks so that the panels and sections can decide whether they can be rendered.
 		api.panel.each( function ( panel ) {
 			var value = panel.active();
 			panel.active.callbacks.fireWith( panel.active, [ value, value ] );
 		} );
 		api.section.each( function ( section ) {
 			var value = section.active();
 			section.active.callbacks.fireWith( section.active, [ value, value ] );
 		} );
 
 		// Restore focus if there was a reflow and there was an active (focused) element.
 		if ( wasReflowed && activeElement ) {
 			activeElement.trigger( 'focus' );
 		}
 		api.trigger( 'pane-contents-reflowed' );
 	}, api );
 
 	// Define state values.
 	api.state = new api.Values();
 	_.each( [
 		'saved',
 		'saving',
 		'trashing',
 		'activated',
 		'processing',
 		'paneVisible',
 		'expandedPanel',
 		'expandedSection',
 		'changesetDate',
 		'selectedChangesetDate',
 		'changesetStatus',
 		'selectedChangesetStatus',
 		'remainingTimeToPublish',
 		'previewerAlive',
 		'editShortcutVisibility',
 		'changesetLocked',
 		'previewedDevice'
 	], function( name ) {
 		api.state.create( name );
 	});
 
 	$( function() {
 		api.settings = window._wpCustomizeSettings;
 		api.l10n = window._wpCustomizeControlsL10n;
 
 		// Check if we can run the Customizer.
 		if ( ! api.settings ) {
 			return;
 		}
 
 		// Bail if any incompatibilities are found.
 		if ( ! $.support.postMessage || ( ! $.support.cors && api.settings.isCrossDomain ) ) {
 			return;
 		}
 
 		if ( null === api.PreviewFrame.prototype.sensitivity ) {
 			api.PreviewFrame.prototype.sensitivity = api.settings.timeouts.previewFrameSensitivity;
 		}
 		if ( null === api.Previewer.prototype.refreshBuffer ) {
 			api.Previewer.prototype.refreshBuffer = api.settings.timeouts.windowRefresh;
 		}
 
 		var parent,
 			body = $( document.body ),
 			overlay = body.children( '.wp-full-overlay' ),
 			title = $( '#customize-info .panel-title.site-title' ),
 			closeBtn = $( '.customize-controls-close' ),
 			saveBtn = $( '#save' ),
 			btnWrapper = $( '#customize-save-button-wrapper' ),
 			publishSettingsBtn = $( '#publish-settings' ),
 			footerActions = $( '#customize-footer-actions' );
 
 		// Add publish settings section in JS instead of PHP since the Customizer depends on it to function.
 		api.bind( 'ready', function() {
 			api.section.add( new api.OuterSection( 'publish_settings', {
 				title: api.l10n.publishSettings,
 				priority: 0,
 				active: api.settings.theme.active
 			} ) );
 		} );
 
 		// Set up publish settings section and its controls.
 		api.section( 'publish_settings', function( section ) {
 			var updateButtonsState, trashControl, updateSectionActive, isSectionActive, statusControl, dateControl, toggleDateControl, publishWhenTime, pollInterval, updateTimeArrivedPoller, cancelScheduleButtonReminder, timeArrivedPollingInterval = 1000;
 
 			trashControl = new api.Control( 'trash_changeset', {
 				type: 'button',
 				section: section.id,
 				priority: 30,
 				input_attrs: {
 					'class': 'button-link button-link-delete',
 					value: api.l10n.discardChanges
 				}
 			} );
 			api.control.add( trashControl );
 			trashControl.deferred.embedded.done( function() {
 				trashControl.container.find( '.button-link' ).on( 'click', function() {
 					if ( confirm( api.l10n.trashConfirm ) ) {
 						wp.customize.previewer.trash();
 					}
 				} );
 			} );
 
 			api.control.add( new api.PreviewLinkControl( 'changeset_preview_link', {
 				section: section.id,
 				priority: 100
 			} ) );
 
 			/**
 			 * Return whether the pubish settings section should be active.
 			 *
 			 * @return {boolean} Is section active.
 			 */
 			isSectionActive = function() {
 				if ( ! api.state( 'activated' ).get() ) {
 					return false;
 				}
 				if ( api.state( 'trashing' ).get() || 'trash' === api.state( 'changesetStatus' ).get() ) {
 					return false;
 				}
 				if ( '' === api.state( 'changesetStatus' ).get() && api.state( 'saved' ).get() ) {
 					return false;
 				}
 				return true;
 			};
 
 			// Make sure publish settings are not available while the theme is not active and the customizer is in a published state.
 			section.active.validate = isSectionActive;
 			updateSectionActive = function() {
 				section.active.set( isSectionActive() );
 			};
 			api.state( 'activated' ).bind( updateSectionActive );
 			api.state( 'trashing' ).bind( updateSectionActive );
 			api.state( 'saved' ).bind( updateSectionActive );
 			api.state( 'changesetStatus' ).bind( updateSectionActive );
 			updateSectionActive();
 
 			// Bind visibility of the publish settings button to whether the section is active.
 			updateButtonsState = function() {
 				publishSettingsBtn.toggle( section.active.get() );
 				saveBtn.toggleClass( 'has-next-sibling', section.active.get() );
 			};
 			updateButtonsState();
 			section.active.bind( updateButtonsState );
 
 			function highlightScheduleButton() {
 				if ( ! cancelScheduleButtonReminder ) {
 					cancelScheduleButtonReminder = api.utils.highlightButton( btnWrapper, {
 						delay: 1000,
 
 						/*
 						 * Only abort the reminder when the save button is focused.
 						 * If the user clicks the settings button to toggle the
 						 * settings closed, we'll still remind them.
 						 */
 						focusTarget: saveBtn
 					} );
 				}
 			}
 			function cancelHighlightScheduleButton() {
 				if ( cancelScheduleButtonReminder ) {
 					cancelScheduleButtonReminder();
 					cancelScheduleButtonReminder = null;
 				}
 			}
 			api.state( 'selectedChangesetStatus' ).bind( cancelHighlightScheduleButton );
 
 			section.contentContainer.find( '.customize-action' ).text( api.l10n.updating );
 			section.contentContainer.find( '.customize-section-back' ).removeAttr( 'tabindex' );
 			publishSettingsBtn.prop( 'disabled', false );
 
 			publishSettingsBtn.on( 'click', function( event ) {
 				event.preventDefault();
 				section.expanded.set( ! section.expanded.get() );
 			} );
 
 			section.expanded.bind( function( isExpanded ) {
 				var defaultChangesetStatus;
 				publishSettingsBtn.attr( 'aria-expanded', String( isExpanded ) );
 				publishSettingsBtn.toggleClass( 'active', isExpanded );
 
 				if ( isExpanded ) {
 					cancelHighlightScheduleButton();
 					return;
 				}
 
 				defaultChangesetStatus = api.state( 'changesetStatus' ).get();
 				if ( '' === defaultChangesetStatus || 'auto-draft' === defaultChangesetStatus ) {
 					defaultChangesetStatus = 'publish';
 				}
 
 				if ( api.state( 'selectedChangesetStatus' ).get() !== defaultChangesetStatus ) {
 					highlightScheduleButton();
 				} else if ( 'future' === api.state( 'selectedChangesetStatus' ).get() && api.state( 'selectedChangesetDate' ).get() !== api.state( 'changesetDate' ).get() ) {
 					highlightScheduleButton();
 				}
 			} );
 
 			statusControl = new api.Control( 'changeset_status', {
 				priority: 10,
 				type: 'radio',
 				section: 'publish_settings',
 				setting: api.state( 'selectedChangesetStatus' ),
 				templateId: 'customize-selected-changeset-status-control',
 				label: api.l10n.action,
 				choices: api.settings.changeset.statusChoices
 			} );
 			api.control.add( statusControl );
 
 			dateControl = new api.DateTimeControl( 'changeset_scheduled_date', {
 				priority: 20,
 				section: 'publish_settings',
 				setting: api.state( 'selectedChangesetDate' ),
 				minYear: ( new Date() ).getFullYear(),
 				allowPastDate: false,
 				includeTime: true,
 				twelveHourFormat: /a/i.test( api.settings.timeFormat ),
 				description: api.l10n.scheduleDescription
 			} );
 			dateControl.notifications.alt = true;
 			api.control.add( dateControl );
 
 			publishWhenTime = function() {
 				api.state( 'selectedChangesetStatus' ).set( 'publish' );
 				api.previewer.save();
 			};
 
 			// Start countdown for when the dateTime arrives, or clear interval when it is .
 			updateTimeArrivedPoller = function() {
 				var shouldPoll = (
 					'future' === api.state( 'changesetStatus' ).get() &&
 					'future' === api.state( 'selectedChangesetStatus' ).get() &&
 					api.state( 'changesetDate' ).get() &&
 					api.state( 'selectedChangesetDate' ).get() === api.state( 'changesetDate' ).get() &&
 					api.utils.getRemainingTime( api.state( 'changesetDate' ).get() ) >= 0
 				);
 
 				if ( shouldPoll && ! pollInterval ) {
 					pollInterval = setInterval( function() {
 						var remainingTime = api.utils.getRemainingTime( api.state( 'changesetDate' ).get() );
 						api.state( 'remainingTimeToPublish' ).set( remainingTime );
 						if ( remainingTime <= 0 ) {
 							clearInterval( pollInterval );
 							pollInterval = 0;
 							publishWhenTime();
 						}
 					}, timeArrivedPollingInterval );
 				} else if ( ! shouldPoll && pollInterval ) {
 					clearInterval( pollInterval );
 					pollInterval = 0;
 				}
 			};
 
 			api.state( 'changesetDate' ).bind( updateTimeArrivedPoller );
 			api.state( 'selectedChangesetDate' ).bind( updateTimeArrivedPoller );
 			api.state( 'changesetStatus' ).bind( updateTimeArrivedPoller );
 			api.state( 'selectedChangesetStatus' ).bind( updateTimeArrivedPoller );
 			updateTimeArrivedPoller();
 
 			// Ensure dateControl only appears when selected status is future.
 			dateControl.active.validate = function() {
 				return 'future' === api.state( 'selectedChangesetStatus' ).get();
 			};
 			toggleDateControl = function( value ) {
 				dateControl.active.set( 'future' === value );
 			};
 			toggleDateControl( api.state( 'selectedChangesetStatus' ).get() );
 			api.state( 'selectedChangesetStatus' ).bind( toggleDateControl );
 
 			// Show notification on date control when status is future but it isn't a future date.
 			api.state( 'saving' ).bind( function( isSaving ) {
 				if ( isSaving && 'future' === api.state( 'selectedChangesetStatus' ).get() ) {
 					dateControl.toggleFutureDateNotification( ! dateControl.isFutureDate() );
 				}
 			} );
 		} );
 
 		// Prevent the form from saving when enter is pressed on an input or select element.
 		$('#customize-controls').on( 'keydown', function( e ) {
 			var isEnter = ( 13 === e.which ),
 				$el = $( e.target );
 
 			if ( isEnter && ( $el.is( 'input:not([type=button])' ) || $el.is( 'select' ) ) ) {
 				e.preventDefault();
 			}
 		});
 
 		// Expand/Collapse the main customizer customize info.
 		$( '.customize-info' ).find( '> .accordion-section-title .customize-help-toggle' ).on( 'click', function() {
 			var section = $( this ).closest( '.accordion-section' ),
 				content = section.find( '.customize-panel-description:first' );
 
 			if ( section.hasClass( 'cannot-expand' ) ) {
 				return;
 			}
 
 			if ( section.hasClass( 'open' ) ) {
 				section.toggleClass( 'open' );
 				content.slideUp( api.Panel.prototype.defaultExpandedArguments.duration, function() {
 					content.trigger( 'toggled' );
 				} );
 				$( this ).attr( 'aria-expanded', false );
 			} else {
 				content.slideDown( api.Panel.prototype.defaultExpandedArguments.duration, function() {
 					content.trigger( 'toggled' );
 				} );
 				section.toggleClass( 'open' );
 				$( this ).attr( 'aria-expanded', true );
 			}
 		});
 
 		/**
 		 * Initialize Previewer
 		 *
 		 * @alias wp.customize.previewer
 		 */
 		api.previewer = new api.Previewer({
 			container:   '#customize-preview',
 			form:        '#customize-controls',
 			previewUrl:  api.settings.url.preview,
 			allowedUrls: api.settings.url.allowed
 		},/** @lends wp.customize.previewer */{
 
 			nonce: api.settings.nonce,
 
 			/**
 			 * Build the query to send along with the Preview request.
 			 *
 			 * @since 3.4.0
 			 * @since 4.7.0 Added options param.
 			 * @access public
 			 *
 			 * @param {Object}  [options] Options.
 			 * @param {boolean} [options.excludeCustomizedSaved=false] Exclude saved settings in customized response (values pending writing to changeset).
 			 * @return {Object} Query vars.
 			 */
 			query: function( options ) {
 				var queryVars = {
 					wp_customize: 'on',
 					customize_theme: api.settings.theme.stylesheet,
 					nonce: this.nonce.preview,
 					customize_changeset_uuid: api.settings.changeset.uuid
 				};
 				if ( api.settings.changeset.autosaved || ! api.state( 'saved' ).get() ) {
 					queryVars.customize_autosaved = 'on';
 				}
 
 				/*
 				 * Exclude customized data if requested especially for calls to requestChangesetUpdate.
 				 * Changeset updates are differential and so it is a performance waste to send all of
 				 * the dirty settings with each update.
 				 */
 				queryVars.customized = JSON.stringify( api.dirtyValues( {
 					unsaved: options && options.excludeCustomizedSaved
 				} ) );
 
 				return queryVars;
 			},
 
 			/**
 			 * Save (and publish) the customizer changeset.
 			 *
 			 * Updates to the changeset are transactional. If any of the settings
 			 * are invalid then none of them will be written into the changeset.
 			 * A revision will be made for the changeset post if revisions support
 			 * has been added to the post type.
 			 *
 			 * @since 3.4.0
 			 * @since 4.7.0 Added args param and return value.
 			 *
 			 * @param {Object} [args] Args.
 			 * @param {string} [args.status=publish] Status.
 			 * @param {string} [args.date] Date, in local time in MySQL format.
 			 * @param {string} [args.title] Title
 			 * @return {jQuery.promise} Promise.
 			 */
 			save: function( args ) {
 				var previewer = this,
 					deferred = $.Deferred(),
 					changesetStatus = api.state( 'selectedChangesetStatus' ).get(),
 					selectedChangesetDate = api.state( 'selectedChangesetDate' ).get(),
 					processing = api.state( 'processing' ),
 					submitWhenDoneProcessing,
 					submit,
 					modifiedWhileSaving = {},
 					invalidSettings = [],
 					invalidControls = [],
 					invalidSettingLessControls = [];
 
 				if ( args && args.status ) {
 					changesetStatus = args.status;
 				}
 
 				if ( api.state( 'saving' ).get() ) {
 					deferred.reject( 'already_saving' );
 					deferred.promise();
 				}
 
 				api.state( 'saving' ).set( true );
 
 				function captureSettingModifiedDuringSave( setting ) {
 					modifiedWhileSaving[ setting.id ] = true;
 				}
 
 				submit = function () {
 					var request, query, settingInvalidities = {}, latestRevision = api._latestRevision, errorCode = 'client_side_error';
 
 					api.bind( 'change', captureSettingModifiedDuringSave );
 					api.notifications.remove( errorCode );
 
 					/*
 					 * Block saving if there are any settings that are marked as
 					 * invalid from the client (not from the server). Focus on
 					 * the control.
 					 */
 					api.each( function( setting ) {
 						setting.notifications.each( function( notification ) {
 							if ( 'error' === notification.type && ! notification.fromServer ) {
 								invalidSettings.push( setting.id );
 								if ( ! settingInvalidities[ setting.id ] ) {
 									settingInvalidities[ setting.id ] = {};
 								}
 								settingInvalidities[ setting.id ][ notification.code ] = notification;
 							}
 						} );
 					} );
 
 					// Find all invalid setting less controls with notification type error.
 					api.control.each( function( control ) {
 						if ( ! control.setting || ! control.setting.id && control.active.get() ) {
 							control.notifications.each( function( notification ) {
 							    if ( 'error' === notification.type ) {
 								    invalidSettingLessControls.push( [ control ] );
 							    }
 							} );
 						}
 					} );
 
 					invalidControls = _.union( invalidSettingLessControls, _.values( api.findControlsForSettings( invalidSettings ) ) );
 					if ( ! _.isEmpty( invalidControls ) ) {
 
 						invalidControls[0][0].focus();
 						api.unbind( 'change', captureSettingModifiedDuringSave );
 
 						if ( invalidSettings.length ) {
 							api.notifications.add( new api.Notification( errorCode, {
 								message: ( 1 === invalidSettings.length ? api.l10n.saveBlockedError.singular : api.l10n.saveBlockedError.plural ).replace( /%s/g, String( invalidSettings.length ) ),
 								type: 'error',
 								dismissible: true,
 								saveFailure: true
 							} ) );
 						}
 
 						deferred.rejectWith( previewer, [
 							{ setting_invalidities: settingInvalidities }
 						] );
 						api.state( 'saving' ).set( false );
 						return deferred.promise();
 					}
 
 					/*
 					 * Note that excludeCustomizedSaved is intentionally false so that the entire
 					 * set of customized data will be included if bypassed changeset update.
 					 */
 					query = $.extend( previewer.query( { excludeCustomizedSaved: false } ), {
 						nonce: previewer.nonce.save,
 						customize_changeset_status: changesetStatus
 					} );
 
 					if ( args && args.date ) {
 						query.customize_changeset_date = args.date;
 					} else if ( 'future' === changesetStatus && selectedChangesetDate ) {
 						query.customize_changeset_date = selectedChangesetDate;
 					}
 
 					if ( args && args.title ) {
 						query.customize_changeset_title = args.title;
 					}
 
 					// Allow plugins to modify the params included with the save request.
 					api.trigger( 'save-request-params', query );
 
 					/*
 					 * Note that the dirty customized values will have already been set in the
 					 * changeset and so technically query.customized could be deleted. However,
 					 * it is remaining here to make sure that any settings that got updated
 					 * quietly which may have not triggered an update request will also get
 					 * included in the values that get saved to the changeset. This will ensure
 					 * that values that get injected via the saved event will be included in
 					 * the changeset. This also ensures that setting values that were invalid
 					 * will get re-validated, perhaps in the case of settings that are invalid
 					 * due to dependencies on other settings.
 					 */
 					request = wp.ajax.post( 'customize_save', query );
 					api.state( 'processing' ).set( api.state( 'processing' ).get() + 1 );
 
 					api.trigger( 'save', request );
 
 					request.always( function () {
 						api.state( 'processing' ).set( api.state( 'processing' ).get() - 1 );
 						api.state( 'saving' ).set( false );
 						api.unbind( 'change', captureSettingModifiedDuringSave );
 					} );
 
 					// Remove notifications that were added due to save failures.
 					api.notifications.each( function( notification ) {
 						if ( notification.saveFailure ) {
 							api.notifications.remove( notification.code );
 						}
 					});
 
 					request.fail( function ( response ) {
 						var notification, notificationArgs;
 						notificationArgs = {
 							type: 'error',
 							dismissible: true,
 							fromServer: true,
 							saveFailure: true
 						};
 
 						if ( '0' === response ) {
 							response = 'not_logged_in';
 						} else if ( '-1' === response ) {
 							// Back-compat in case any other check_ajax_referer() call is dying.
 							response = 'invalid_nonce';
 						}
 
 						if ( 'invalid_nonce' === response ) {
 							previewer.cheatin();
 						} else if ( 'not_logged_in' === response ) {
 							previewer.preview.iframe.hide();
 							previewer.login().done( function() {
 								previewer.save();
 								previewer.preview.iframe.show();
 							} );
 						} else if ( response.code ) {
 							if ( 'not_future_date' === response.code && api.section.has( 'publish_settings' ) && api.section( 'publish_settings' ).active.get() && api.control.has( 'changeset_scheduled_date' ) ) {
 								api.control( 'changeset_scheduled_date' ).toggleFutureDateNotification( true ).focus();
 							} else if ( 'changeset_locked' !== response.code ) {
 								notification = new api.Notification( response.code, _.extend( notificationArgs, {
 									message: response.message
 								} ) );
 							}
 						} else {
 							notification = new api.Notification( 'unknown_error', _.extend( notificationArgs, {
 								message: api.l10n.unknownRequestFail
 							} ) );
 						}
 
 						if ( notification ) {
 							api.notifications.add( notification );
 						}
 
 						if ( response.setting_validities ) {
 							api._handleSettingValidities( {
 								settingValidities: response.setting_validities,
 								focusInvalidControl: true
 							} );
 						}
 
 						deferred.rejectWith( previewer, [ response ] );
 						api.trigger( 'error', response );
 
 						// Start a new changeset if the underlying changeset was published.
 						if ( 'changeset_already_published' === response.code && response.next_changeset_uuid ) {
 							api.settings.changeset.uuid = response.next_changeset_uuid;
 							api.state( 'changesetStatus' ).set( '' );
 							if ( api.settings.changeset.branching ) {
 								parent.send( 'changeset-uuid', api.settings.changeset.uuid );
 							}
 							api.previewer.send( 'changeset-uuid', api.settings.changeset.uuid );
 						}
 					} );
 
 					request.done( function( response ) {
 
 						previewer.send( 'saved', response );
 
 						api.state( 'changesetStatus' ).set( response.changeset_status );
 						if ( response.changeset_date ) {
 							api.state( 'changesetDate' ).set( response.changeset_date );
 						}
 
 						if ( 'publish' === response.changeset_status ) {
 
 							// Mark all published as clean if they haven't been modified during the request.
 							api.each( function( setting ) {
 								/*
 								 * Note that the setting revision will be undefined in the case of setting
 								 * values that are marked as dirty when the customizer is loaded, such as
 								 * when applying starter content. All other dirty settings will have an
 								 * associated revision due to their modification triggering a change event.
 								 */
 								if ( setting._dirty && ( _.isUndefined( api._latestSettingRevisions[ setting.id ] ) || api._latestSettingRevisions[ setting.id ] <= latestRevision ) ) {
 									setting._dirty = false;
 								}
 							} );
 
 							api.state( 'changesetStatus' ).set( '' );
 							api.settings.changeset.uuid = response.next_changeset_uuid;
 							if ( api.settings.changeset.branching ) {
 								parent.send( 'changeset-uuid', api.settings.changeset.uuid );
 							}
 						}
 
 						// Prevent subsequent requestChangesetUpdate() calls from including the settings that have been saved.
 						api._lastSavedRevision = Math.max( latestRevision, api._lastSavedRevision );
 
 						if ( response.setting_validities ) {
 							api._handleSettingValidities( {
 								settingValidities: response.setting_validities,
 								focusInvalidControl: true
 							} );
 						}
 
 						deferred.resolveWith( previewer, [ response ] );
 						api.trigger( 'saved', response );
 
 						// Restore the global dirty state if any settings were modified during save.
 						if ( ! _.isEmpty( modifiedWhileSaving ) ) {
 							api.state( 'saved' ).set( false );
 						}
 					} );
 				};
 
 				if ( 0 === processing() ) {
 					submit();
 				} else {
 					submitWhenDoneProcessing = function () {
 						if ( 0 === processing() ) {
 							api.state.unbind( 'change', submitWhenDoneProcessing );
 							submit();
 						}
 					};
 					api.state.bind( 'change', submitWhenDoneProcessing );
 				}
 
 				return deferred.promise();
 			},
 
 			/**
 			 * Trash the current changes.
 			 *
 			 * Revert the Customizer to its previously-published state.
 			 *
 			 * @since 4.9.0
 			 *
 			 * @return {jQuery.promise} Promise.
 			 */
 			trash: function trash() {
 				var request, success, fail;
 
 				api.state( 'trashing' ).set( true );
 				api.state( 'processing' ).set( api.state( 'processing' ).get() + 1 );
 
 				request = wp.ajax.post( 'customize_trash', {
 					customize_changeset_uuid: api.settings.changeset.uuid,
 					nonce: api.settings.nonce.trash
 				} );
 				api.notifications.add( new api.OverlayNotification( 'changeset_trashing', {
 					type: 'info',
 					message: api.l10n.revertingChanges,
 					loading: true
 				} ) );
 
 				success = function() {
 					var urlParser = document.createElement( 'a' ), queryParams;
 
 					api.state( 'changesetStatus' ).set( 'trash' );
 					api.each( function( setting ) {
 						setting._dirty = false;
 					} );
 					api.state( 'saved' ).set( true );
 
 					// Go back to Customizer without changeset.
 					urlParser.href = location.href;
 					queryParams = api.utils.parseQueryString( urlParser.search.substr( 1 ) );
 					delete queryParams.changeset_uuid;
 					queryParams['return'] = api.settings.url['return'];
 					urlParser.search = $.param( queryParams );
 					location.replace( urlParser.href );
 				};
 
 				fail = function( code, message ) {
 					var notificationCode = code || 'unknown_error';
 					api.state( 'processing' ).set( api.state( 'processing' ).get() - 1 );
 					api.state( 'trashing' ).set( false );
 					api.notifications.remove( 'changeset_trashing' );
 					api.notifications.add( new api.Notification( notificationCode, {
 						message: message || api.l10n.unknownError,
 						dismissible: true,
 						type: 'error'
 					} ) );
 				};
 
 				request.done( function( response ) {
 					success( response.message );
 				} );
 
 				request.fail( function( response ) {
 					var code = response.code || 'trashing_failed';
 					if ( response.success || 'non_existent_changeset' === code || 'changeset_already_trashed' === code ) {
 						success( response.message );
 					} else {
 						fail( code, response.message );
 					}
 				} );
 			},
 
 			/**
 			 * Builds the front preview url with the current state of customizer.
 			 *
 			 * @since 4.9
 			 *
 			 * @return {string} Preview url.
 			 */
 			getFrontendPreviewUrl: function() {
 				var previewer = this, params, urlParser;
 				urlParser = document.createElement( 'a' );
 				urlParser.href = previewer.previewUrl.get();
 				params = api.utils.parseQueryString( urlParser.search.substr( 1 ) );
 
 				if ( api.state( 'changesetStatus' ).get() && 'publish' !== api.state( 'changesetStatus' ).get() ) {
 					params.customize_changeset_uuid = api.settings.changeset.uuid;
 				}
 				if ( ! api.state( 'activated' ).get() ) {
 					params.customize_theme = api.settings.theme.stylesheet;
 				}
 
 				urlParser.search = $.param( params );
 				return urlParser.href;
 			}
 		});
 
 		// Ensure preview nonce is included with every customized request, to allow post data to be read.
 		$.ajaxPrefilter( function injectPreviewNonce( options ) {
 			if ( ! /wp_customize=on/.test( options.data ) ) {
 				return;
 			}
 			options.data += '&' + $.param({
 				customize_preview_nonce: api.settings.nonce.preview
 			});
 		});
 
 		// Refresh the nonces if the preview sends updated nonces over.
 		api.previewer.bind( 'nonce', function( nonce ) {
 			$.extend( this.nonce, nonce );
 		});
 
 		// Refresh the nonces if login sends updated nonces over.
 		api.bind( 'nonce-refresh', function( nonce ) {
 			$.extend( api.settings.nonce, nonce );
 			$.extend( api.previewer.nonce, nonce );
 			api.previewer.send( 'nonce-refresh', nonce );
 		});
 
 		// Create Settings.
 		$.each( api.settings.settings, function( id, data ) {
 			var Constructor = api.settingConstructor[ data.type ] || api.Setting;
 			api.add( new Constructor( id, data.value, {
 				transport: data.transport,
 				previewer: api.previewer,
 				dirty: !! data.dirty
 			} ) );
 		});
 
 		// Create Panels.
 		$.each( api.settings.panels, function ( id, data ) {
 			var Constructor = api.panelConstructor[ data.type ] || api.Panel, options;
 			// Inclusion of params alias is for back-compat for custom panels that expect to augment this property.
 			options = _.extend( { params: data }, data );
 			api.panel.add( new Constructor( id, options ) );
 		});
 
 		// Create Sections.
 		$.each( api.settings.sections, function ( id, data ) {
 			var Constructor = api.sectionConstructor[ data.type ] || api.Section, options;
 			// Inclusion of params alias is for back-compat for custom sections that expect to augment this property.
 			options = _.extend( { params: data }, data );
 			api.section.add( new Constructor( id, options ) );
 		});
 
 		// Create Controls.
 		$.each( api.settings.controls, function( id, data ) {
 			var Constructor = api.controlConstructor[ data.type ] || api.Control, options;
 			// Inclusion of params alias is for back-compat for custom controls that expect to augment this property.
 			options = _.extend( { params: data }, data );
 			api.control.add( new Constructor( id, options ) );
 		});
 
 		// Focus the autofocused element.
 		_.each( [ 'panel', 'section', 'control' ], function( type ) {
 			var id = api.settings.autofocus[ type ];
 			if ( ! id ) {
 				return;
 			}
 
 			/*
 			 * Defer focus until:
 			 * 1. The panel, section, or control exists (especially for dynamically-created ones).
 			 * 2. The instance is embedded in the document (and so is focusable).
 			 * 3. The preview has finished loading so that the active states have been set.
 			 */
 			api[ type ]( id, function( instance ) {
 				instance.deferred.embedded.done( function() {
 					api.previewer.deferred.active.done( function() {
 						instance.focus();
 					});
 				});
 			});
 		});
 
 		api.bind( 'ready', api.reflowPaneContents );
 		$( [ api.panel, api.section, api.control ] ).each( function ( i, values ) {
 			var debouncedReflowPaneContents = _.debounce( api.reflowPaneContents, api.settings.timeouts.reflowPaneContents );
 			values.bind( 'add', debouncedReflowPaneContents );
 			values.bind( 'change', debouncedReflowPaneContents );
 			values.bind( 'remove', debouncedReflowPaneContents );
 		} );
 
 		// Set up global notifications area.
 		api.bind( 'ready', function setUpGlobalNotificationsArea() {
 			var sidebar, containerHeight, containerInitialTop;
 			api.notifications.container = $( '#customize-notifications-area' );
 
 			api.notifications.bind( 'change', _.debounce( function() {
 				api.notifications.render();
 			} ) );
 
 			sidebar = $( '.wp-full-overlay-sidebar-content' );
 			api.notifications.bind( 'rendered', function updateSidebarTop() {
 				sidebar.css( 'top', '' );
 				if ( 0 !== api.notifications.count() ) {
 					containerHeight = api.notifications.container.outerHeight() + 1;
 					containerInitialTop = parseInt( sidebar.css( 'top' ), 10 );
 					sidebar.css( 'top', containerInitialTop + containerHeight + 'px' );
 				}
 				api.notifications.trigger( 'sidebarTopUpdated' );
 			});
 
 			api.notifications.render();
 		});
 
 		// Save and activated states.
 		(function( state ) {
 			var saved = state.instance( 'saved' ),
 				saving = state.instance( 'saving' ),
 				trashing = state.instance( 'trashing' ),
 				activated = state.instance( 'activated' ),
 				processing = state.instance( 'processing' ),
 				paneVisible = state.instance( 'paneVisible' ),
 				expandedPanel = state.instance( 'expandedPanel' ),
 				expandedSection = state.instance( 'expandedSection' ),
 				changesetStatus = state.instance( 'changesetStatus' ),
 				selectedChangesetStatus = state.instance( 'selectedChangesetStatus' ),
 				changesetDate = state.instance( 'changesetDate' ),
 				selectedChangesetDate = state.instance( 'selectedChangesetDate' ),
 				previewerAlive = state.instance( 'previewerAlive' ),
 				editShortcutVisibility  = state.instance( 'editShortcutVisibility' ),
 				changesetLocked = state.instance( 'changesetLocked' ),
 				populateChangesetUuidParam, defaultSelectedChangesetStatus;
 
 			state.bind( 'change', function() {
 				var canSave;
 
 				if ( ! activated() ) {
 					saveBtn.val( api.l10n.activate );
 					closeBtn.find( '.screen-reader-text' ).text( api.l10n.cancel );
 
 				} else if ( '' === changesetStatus.get() && saved() ) {
 					if ( api.settings.changeset.currentUserCanPublish ) {
 						saveBtn.val( api.l10n.published );
 					} else {
 						saveBtn.val( api.l10n.saved );
 					}
 					closeBtn.find( '.screen-reader-text' ).text( api.l10n.close );
 
 				} else {
 					if ( 'draft' === selectedChangesetStatus() ) {
 						if ( saved() && selectedChangesetStatus() === changesetStatus() ) {
 							saveBtn.val( api.l10n.draftSaved );
 						} else {
 							saveBtn.val( api.l10n.saveDraft );
 						}
 					} else if ( 'future' === selectedChangesetStatus() ) {
 						if ( saved() && selectedChangesetStatus() === changesetStatus() ) {
 							if ( changesetDate.get() !== selectedChangesetDate.get() ) {
 								saveBtn.val( api.l10n.schedule );
 							} else {
 								saveBtn.val( api.l10n.scheduled );
 							}
 						} else {
 							saveBtn.val( api.l10n.schedule );
 						}
 					} else if ( api.settings.changeset.currentUserCanPublish ) {
 						saveBtn.val( api.l10n.publish );
 					}
 					closeBtn.find( '.screen-reader-text' ).text( api.l10n.cancel );
 				}
 
 				/*
 				 * Save (publish) button should be enabled if saving is not currently happening,
 				 * and if the theme is not active or the changeset exists but is not published.
 				 */
 				canSave = ! saving() && ! trashing() && ! changesetLocked() && ( ! activated() || ! saved() || ( changesetStatus() !== selectedChangesetStatus() && '' !== changesetStatus() ) || ( 'future' === selectedChangesetStatus() && changesetDate.get() !== selectedChangesetDate.get() ) );
 
 				saveBtn.prop( 'disabled', ! canSave );
 			});
 
 			selectedChangesetStatus.validate = function( status ) {
 				if ( '' === status || 'auto-draft' === status ) {
 					return null;
 				}
 				return status;
 			};
 
 			defaultSelectedChangesetStatus = api.settings.changeset.currentUserCanPublish ? 'publish' : 'draft';
 
 			// Set default states.
 			changesetStatus( api.settings.changeset.status );
 			changesetLocked( Boolean( api.settings.changeset.lockUser ) );
 			changesetDate( api.settings.changeset.publishDate );
 			selectedChangesetDate( api.settings.changeset.publishDate );
 			selectedChangesetStatus( '' === api.settings.changeset.status || 'auto-draft' === api.settings.changeset.status ? defaultSelectedChangesetStatus : api.settings.changeset.status );
 			selectedChangesetStatus.link( changesetStatus ); // Ensure that direct updates to status on server via wp.customizer.previewer.save() will update selection.
 			saved( true );
 			if ( '' === changesetStatus() ) { // Handle case for loading starter content.
 				api.each( function( setting ) {
 					if ( setting._dirty ) {
 						saved( false );
 					}
 				} );
 			}
 			saving( false );
 			activated( api.settings.theme.active );
 			processing( 0 );
 			paneVisible( true );
 			expandedPanel( false );
 			expandedSection( false );
 			previewerAlive( true );
 			editShortcutVisibility( 'visible' );
 
 			api.bind( 'change', function() {
 				if ( state( 'saved' ).get() ) {
 					state( 'saved' ).set( false );
 				}
 			});
 
 			// Populate changeset UUID param when state becomes dirty.
 			if ( api.settings.changeset.branching ) {
 				saved.bind( function( isSaved ) {
 					if ( ! isSaved ) {
 						populateChangesetUuidParam( true );
 					}
 				});
 			}
 
 			saving.bind( function( isSaving ) {
 				body.toggleClass( 'saving', isSaving );
 			} );
 			trashing.bind( function( isTrashing ) {
 				body.toggleClass( 'trashing', isTrashing );
 			} );
 
 			api.bind( 'saved', function( response ) {
 				state('saved').set( true );
 				if ( 'publish' === response.changeset_status ) {
 					state( 'activated' ).set( true );
 				}
 			});
 
 			activated.bind( function( to ) {
 				if ( to ) {
 					api.trigger( 'activated' );
 				}
 			});
 
 			/**
 			 * Populate URL with UUID via `history.replaceState()`.
 			 *
 			 * @since 4.7.0
 			 * @access private
 			 *
 			 * @param {boolean} isIncluded Is UUID included.
 			 * @return {void}
 			 */
 			populateChangesetUuidParam = function( isIncluded ) {
 				var urlParser, queryParams;
 
 				// Abort on IE9 which doesn't support history management.
 				if ( ! history.replaceState ) {
 					return;
 				}
 
 				urlParser = document.createElement( 'a' );
 				urlParser.href = location.href;
 				queryParams = api.utils.parseQueryString( urlParser.search.substr( 1 ) );
 				if ( isIncluded ) {
 					if ( queryParams.changeset_uuid === api.settings.changeset.uuid ) {
 						return;
 					}
 					queryParams.changeset_uuid = api.settings.changeset.uuid;
 				} else {
 					if ( ! queryParams.changeset_uuid ) {
 						return;
 					}
 					delete queryParams.changeset_uuid;
 				}
 				urlParser.search = $.param( queryParams );
 				history.replaceState( {}, document.title, urlParser.href );
 			};
 
 			// Show changeset UUID in URL when in branching mode and there is a saved changeset.
 			if ( api.settings.changeset.branching ) {
 				changesetStatus.bind( function( newStatus ) {
 					populateChangesetUuidParam( '' !== newStatus && 'publish' !== newStatus && 'trash' !== newStatus );
 				} );
 			}
 		}( api.state ) );
 
 		/**
 		 * Handles lock notice and take over request.
 		 *
 		 * @since 4.9.0
 		 */
 		( function checkAndDisplayLockNotice() {
 
 			var LockedNotification = api.OverlayNotification.extend(/** @lends wp.customize~LockedNotification.prototype */{
 
 				/**
 				 * Template ID.
 				 *
 				 * @type {string}
 				 */
 				templateId: 'customize-changeset-locked-notification',
 
 				/**
 				 * Lock user.
 				 *
 				 * @type {object}
 				 */
 				lockUser: null,
 
 				/**
 				 * A notification that is displayed in a full-screen overlay with information about the locked changeset.
 				 *
 				 * @constructs wp.customize~LockedNotification
 				 * @augments   wp.customize.OverlayNotification
 				 *
 				 * @since 4.9.0
 				 *
 				 * @param {string} [code] - Code.
 				 * @param {Object} [params] - Params.
 				 */
 				initialize: function( code, params ) {
 					var notification = this, _code, _params;
 					_code = code || 'changeset_locked';
 					_params = _.extend(
 						{
 							message: '',
 							type: 'warning',
 							containerClasses: '',
 							lockUser: {}
 						},
 						params
 					);
 					_params.containerClasses += ' notification-changeset-locked';
 					api.OverlayNotification.prototype.initialize.call( notification, _code, _params );
 				},
 
 				/**
 				 * Render notification.
 				 *
 				 * @since 4.9.0
 				 *
 				 * @return {jQuery} Notification container.
 				 */
 				render: function() {
 					var notification = this, li, data, takeOverButton, request;
 					data = _.extend(
 						{
 							allowOverride: false,
 							returnUrl: api.settings.url['return'],
 							previewUrl: api.previewer.previewUrl.get(),
 							frontendPreviewUrl: api.previewer.getFrontendPreviewUrl()
 						},
 						this
 					);
 
 					li = api.OverlayNotification.prototype.render.call( data );
 
 					// Try to autosave the changeset now.
 					api.requestChangesetUpdate( {}, { autosave: true } ).fail( function( response ) {
 						if ( ! response.autosaved ) {
 							li.find( '.notice-error' ).prop( 'hidden', false ).text( response.message || api.l10n.unknownRequestFail );
 						}
 					} );
 
 					takeOverButton = li.find( '.customize-notice-take-over-button' );
 					takeOverButton.on( 'click', function( event ) {
 						event.preventDefault();
 						if ( request ) {
 							return;
 						}
 
 						takeOverButton.addClass( 'disabled' );
 						request = wp.ajax.post( 'customize_override_changeset_lock', {
 							wp_customize: 'on',
 							customize_theme: api.settings.theme.stylesheet,
 							customize_changeset_uuid: api.settings.changeset.uuid,
 							nonce: api.settings.nonce.override_lock
 						} );
 
 						request.done( function() {
 							api.notifications.remove( notification.code ); // Remove self.
 							api.state( 'changesetLocked' ).set( false );
 						} );
 
 						request.fail( function( response ) {
 							var message = response.message || api.l10n.unknownRequestFail;
 							li.find( '.notice-error' ).prop( 'hidden', false ).text( message );
 
 							request.always( function() {
 								takeOverButton.removeClass( 'disabled' );
 							} );
 						} );
 
 						request.always( function() {
 							request = null;
 						} );
 					} );
 
 					return li;
 				}
 			});
 
 			/**
 			 * Start lock.
 			 *
 			 * @since 4.9.0
 			 *
 			 * @param {Object} [args] - Args.
 			 * @param {Object} [args.lockUser] - Lock user data.
 			 * @param {boolean} [args.allowOverride=false] - Whether override is allowed.
 			 * @return {void}
 			 */
 			function startLock( args ) {
 				if ( args && args.lockUser ) {
 					api.settings.changeset.lockUser = args.lockUser;
 				}
 				api.state( 'changesetLocked' ).set( true );
 				api.notifications.add( new LockedNotification( 'changeset_locked', {
 					lockUser: api.settings.changeset.lockUser,
 					allowOverride: Boolean( args && args.allowOverride )
 				} ) );
 			}
 
 			// Show initial notification.
 			if ( api.settings.changeset.lockUser ) {
 				startLock( { allowOverride: true } );
 			}
 
 			// Check for lock when sending heartbeat requests.
 			$( document ).on( 'heartbeat-send.update_lock_notice', function( event, data ) {
 				data.check_changeset_lock = true;
 				data.changeset_uuid = api.settings.changeset.uuid;
 			} );
 
 			// Handle heartbeat ticks.
 			$( document ).on( 'heartbeat-tick.update_lock_notice', function( event, data ) {
 				var notification, code = 'changeset_locked';
 				if ( ! data.customize_changeset_lock_user ) {
 					return;
 				}
 
 				// Update notification when a different user takes over.
 				notification = api.notifications( code );
 				if ( notification && notification.lockUser.id !== api.settings.changeset.lockUser.id ) {
 					api.notifications.remove( code );
 				}
 
 				startLock( {
 					lockUser: data.customize_changeset_lock_user
 				} );
 			} );
 
 			// Handle locking in response to changeset save errors.
 			api.bind( 'error', function( response ) {
 				if ( 'changeset_locked' === response.code && response.lock_user ) {
 					startLock( {
 						lockUser: response.lock_user
 					} );
 				}
 			} );
 		} )();
 
 		// Set up initial notifications.
 		(function() {
 			var removedQueryParams = [], autosaveDismissed = false;
 
 			/**
 			 * Obtain the URL to restore the autosave.
 			 *
 			 * @return {string} Customizer URL.
 			 */
 			function getAutosaveRestorationUrl() {
 				var urlParser, queryParams;
 				urlParser = document.createElement( 'a' );
 				urlParser.href = location.href;
 				queryParams = api.utils.parseQueryString( urlParser.search.substr( 1 ) );
 				if ( api.settings.changeset.latestAutoDraftUuid ) {
 					queryParams.changeset_uuid = api.settings.changeset.latestAutoDraftUuid;
 				} else {
 					queryParams.customize_autosaved = 'on';
 				}
 				queryParams['return'] = api.settings.url['return'];
 				urlParser.search = $.param( queryParams );
 				return urlParser.href;
 			}
 
 			/**
 			 * Remove parameter from the URL.
 			 *
 			 * @param {Array} params - Parameter names to remove.
 			 * @return {void}
 			 */
 			function stripParamsFromLocation( params ) {
 				var urlParser = document.createElement( 'a' ), queryParams, strippedParams = 0;
 				urlParser.href = location.href;
 				queryParams = api.utils.parseQueryString( urlParser.search.substr( 1 ) );
 				_.each( params, function( param ) {
 					if ( 'undefined' !== typeof queryParams[ param ] ) {
 						strippedParams += 1;
 						delete queryParams[ param ];
 					}
 				} );
 				if ( 0 === strippedParams ) {
 					return;
 				}
 
 				urlParser.search = $.param( queryParams );
 				history.replaceState( {}, document.title, urlParser.href );
 			}
 
 			/**
 			 * Dismiss autosave.
 			 *
 			 * @return {void}
 			 */
 			function dismissAutosave() {
 				if ( autosaveDismissed ) {
 					return;
 				}
 				wp.ajax.post( 'customize_dismiss_autosave_or_lock', {
 					wp_customize: 'on',
 					customize_theme: api.settings.theme.stylesheet,
 					customize_changeset_uuid: api.settings.changeset.uuid,
 					nonce: api.settings.nonce.dismiss_autosave_or_lock,
 					dismiss_autosave: true
 				} );
 				autosaveDismissed = true;
 			}
 
 			/**
 			 * Add notification regarding the availability of an autosave to restore.
 			 *
 			 * @return {void}
 			 */
 			function addAutosaveRestoreNotification() {
 				var code = 'autosave_available', onStateChange;
 
 				// Since there is an autosave revision and the user hasn't loaded with autosaved, add notification to prompt to load autosaved version.
 				api.notifications.add( new api.Notification( code, {
 					message: api.l10n.autosaveNotice,
 					type: 'warning',
 					dismissible: true,
 					render: function() {
 						var li = api.Notification.prototype.render.call( this ), link;
 
 						// Handle clicking on restoration link.
 						link = li.find( 'a' );
 						link.prop( 'href', getAutosaveRestorationUrl() );
 						link.on( 'click', function( event ) {
 							event.preventDefault();
 							location.replace( getAutosaveRestorationUrl() );
 						} );
 
 						// Handle dismissal of notice.
 						li.find( '.notice-dismiss' ).on( 'click', dismissAutosave );
 
 						return li;
 					}
 				} ) );
 
 				// Remove the notification once the user starts making changes.
 				onStateChange = function() {
 					dismissAutosave();
 					api.notifications.remove( code );
 					api.unbind( 'change', onStateChange );
 					api.state( 'changesetStatus' ).unbind( onStateChange );
 				};
 				api.bind( 'change', onStateChange );
 				api.state( 'changesetStatus' ).bind( onStateChange );
 			}
 
 			if ( api.settings.changeset.autosaved ) {
 				api.state( 'saved' ).set( false );
 				removedQueryParams.push( 'customize_autosaved' );
 			}
 			if ( ! api.settings.changeset.branching && ( ! api.settings.changeset.status || 'auto-draft' === api.settings.changeset.status ) ) {
 				removedQueryParams.push( 'changeset_uuid' ); // Remove UUID when restoring autosave auto-draft.
 			}
 			if ( removedQueryParams.length > 0 ) {
 				stripParamsFromLocation( removedQueryParams );
 			}
 			if ( api.settings.changeset.latestAutoDraftUuid || api.settings.changeset.hasAutosaveRevision ) {
 				addAutosaveRestoreNotification();
 			}
 		})();
 
 		// Check if preview url is valid and load the preview frame.
 		if ( api.previewer.previewUrl() ) {
 			api.previewer.refresh();
 		} else {
 			api.previewer.previewUrl( api.settings.url.home );
 		}
 
 		// Button bindings.
 		saveBtn.on( 'click', function( event ) {
 			api.previewer.save();
 			event.preventDefault();
 		}).on( 'keydown', function( event ) {
 			if ( 9 === event.which ) { // Tab.
 				return;
 			}
 			if ( 13 === event.which ) { // Enter.
 				api.previewer.save();
 			}
 			event.preventDefault();
 		});
 
 		closeBtn.on( 'keydown', function( event ) {
 			if ( 9 === event.which ) { // Tab.
 				return;
 			}
 			if ( 13 === event.which ) { // Enter.
 				this.click();
 			}
 			event.preventDefault();
 		});
 
 		$( '.collapse-sidebar' ).on( 'click', function() {
 			api.state( 'paneVisible' ).set( ! api.state( 'paneVisible' ).get() );
 		});
 
 		api.state( 'paneVisible' ).bind( function( paneVisible ) {
 			overlay.toggleClass( 'preview-only', ! paneVisible );
 			overlay.toggleClass( 'expanded', paneVisible );
 			overlay.toggleClass( 'collapsed', ! paneVisible );
 
 			if ( ! paneVisible ) {
 				$( '.collapse-sidebar' ).attr({ 'aria-expanded': 'false', 'aria-label': api.l10n.expandSidebar });
 			} else {
 				$( '.collapse-sidebar' ).attr({ 'aria-expanded': 'true', 'aria-label': api.l10n.collapseSidebar });
 			}
 		});
 
 		// Keyboard shortcuts - esc to exit section/panel.
 		body.on( 'keydown', function( event ) {
 			var collapsedObject, expandedControls = [], expandedSections = [], expandedPanels = [];
 
 			if ( 27 !== event.which ) { // Esc.
 				return;
 			}
 
 			/*
 			 * Abort if the event target is not the body (the default) and not inside of #customize-controls.
 			 * This ensures that ESC meant to collapse a modal dialog or a TinyMCE toolbar won't collapse something else.
 			 */
 			if ( ! $( event.target ).is( 'body' ) && ! $.contains( $( '#customize-controls' )[0], event.target ) ) {
 				return;
 			}
 
 			// Abort if we're inside of a block editor instance.
 			if ( event.target.closest( '.block-editor-writing-flow' ) !== null ||
 				event.target.closest( '.block-editor-block-list__block-popover' ) !== null
 			) {
 				return;
 			}
 
 			// Check for expanded expandable controls (e.g. widgets and nav menus items), sections, and panels.
 			api.control.each( function( control ) {
 				if ( control.expanded && control.expanded() && _.isFunction( control.collapse ) ) {
 					expandedControls.push( control );
 				}
 			});
 			api.section.each( function( section ) {
 				if ( section.expanded() ) {
 					expandedSections.push( section );
 				}
 			});
 			api.panel.each( function( panel ) {
 				if ( panel.expanded() ) {
 					expandedPanels.push( panel );
 				}
 			});
 
 			// Skip collapsing expanded controls if there are no expanded sections.
 			if ( expandedControls.length > 0 && 0 === expandedSections.length ) {
 				expandedControls.length = 0;
 			}
 
 			// Collapse the most granular expanded object.
 			collapsedObject = expandedControls[0] || expandedSections[0] || expandedPanels[0];
 			if ( collapsedObject ) {
 				if ( 'themes' === collapsedObject.params.type ) {
 
 					// Themes panel or section.
 					if ( body.hasClass( 'modal-open' ) ) {
 						collapsedObject.closeDetails();
 					} else if ( api.panel.has( 'themes' ) ) {
 
 						// If we're collapsing a section, collapse the panel also.
 						api.panel( 'themes' ).collapse();
 					}
 					return;
 				}
 				collapsedObject.collapse();
 				event.preventDefault();
 			}
 		});
 
 		$( '.customize-controls-preview-toggle' ).on( 'click', function() {
 			api.state( 'paneVisible' ).set( ! api.state( 'paneVisible' ).get() );
 		});
 
 		/*
 		 * Sticky header feature.
 		 */
 		(function initStickyHeaders() {
 			var parentContainer = $( '.wp-full-overlay-sidebar-content' ),
 				changeContainer, updateHeaderHeight, releaseStickyHeader, resetStickyHeader, positionStickyHeader,
 				activeHeader, lastScrollTop;
 
 			/**
 			 * Determine which panel or section is currently expanded.
 			 *
 			 * @since 4.7.0
 			 * @access private
 			 *
 			 * @param {wp.customize.Panel|wp.customize.Section} container Construct.
 			 * @return {void}
 			 */
 			changeContainer = function( container ) {
 				var newInstance = container,
 					expandedSection = api.state( 'expandedSection' ).get(),
 					expandedPanel = api.state( 'expandedPanel' ).get(),
 					headerElement;
 
 				if ( activeHeader && activeHeader.element ) {
 					// Release previously active header element.
 					releaseStickyHeader( activeHeader.element );
 
 					// Remove event listener in the previous panel or section.
 					activeHeader.element.find( '.description' ).off( 'toggled', updateHeaderHeight );
 				}
 
 				if ( ! newInstance ) {
 					if ( ! expandedSection && expandedPanel && expandedPanel.contentContainer ) {
 						newInstance = expandedPanel;
 					} else if ( ! expandedPanel && expandedSection && expandedSection.contentContainer ) {
 						newInstance = expandedSection;
 					} else {
 						activeHeader = false;
 						return;
 					}
 				}
 
 				headerElement = newInstance.contentContainer.find( '.customize-section-title, .panel-meta' ).first();
 				if ( headerElement.length ) {
 					activeHeader = {
 						instance: newInstance,
 						element:  headerElement,
 						parent:   headerElement.closest( '.customize-pane-child' ),
 						height:   headerElement.outerHeight()
 					};
 
 					// Update header height whenever help text is expanded or collapsed.
 					activeHeader.element.find( '.description' ).on( 'toggled', updateHeaderHeight );
 
 					if ( expandedSection ) {
 						resetStickyHeader( activeHeader.element, activeHeader.parent );
 					}
 				} else {
 					activeHeader = false;
 				}
 			};
 			api.state( 'expandedSection' ).bind( changeContainer );
 			api.state( 'expandedPanel' ).bind( changeContainer );
 
 			// Throttled scroll event handler.
 			parentContainer.on( 'scroll', _.throttle( function() {
 				if ( ! activeHeader ) {
 					return;
 				}
 
 				var scrollTop = parentContainer.scrollTop(),
 					scrollDirection;
 
 				if ( ! lastScrollTop ) {
 					scrollDirection = 1;
 				} else {
 					if ( scrollTop === lastScrollTop ) {
 						scrollDirection = 0;
 					} else if ( scrollTop > lastScrollTop ) {
 						scrollDirection = 1;
 					} else {
 						scrollDirection = -1;
 					}
 				}
 				lastScrollTop = scrollTop;
 				if ( 0 !== scrollDirection ) {
 					positionStickyHeader( activeHeader, scrollTop, scrollDirection );
 				}
 			}, 8 ) );
 
 			// Update header position on sidebar layout change.
 			api.notifications.bind( 'sidebarTopUpdated', function() {
 				if ( activeHeader && activeHeader.element.hasClass( 'is-sticky' ) ) {
 					activeHeader.element.css( 'top', parentContainer.css( 'top' ) );
 				}
 			});
 
 			// Release header element if it is sticky.
 			releaseStickyHeader = function( headerElement ) {
 				if ( ! headerElement.hasClass( 'is-sticky' ) ) {
 					return;
 				}
 				headerElement
 					.removeClass( 'is-sticky' )
 					.addClass( 'maybe-sticky is-in-view' )
 					.css( 'top', parentContainer.scrollTop() + 'px' );
 			};
 
 			// Reset position of the sticky header.
 			resetStickyHeader = function( headerElement, headerParent ) {
 				if ( headerElement.hasClass( 'is-in-view' ) ) {
 					headerElement
 						.removeClass( 'maybe-sticky is-in-view' )
 						.css( {
 							width: '',
 							top:   ''
 						} );
 					headerParent.css( 'padding-top', '' );
 				}
 			};
 
 			/**
 			 * Update active header height.
 			 *
 			 * @since 4.7.0
 			 * @access private
 			 *
 			 * @return {void}
 			 */
 			updateHeaderHeight = function() {
 				activeHeader.height = activeHeader.element.outerHeight();
 			};
 
 			/**
 			 * Reposition header on throttled `scroll` event.
 			 *
 			 * @since 4.7.0
 			 * @access private
 			 *
 			 * @param {Object} header - Header.
 			 * @param {number} scrollTop - Scroll top.
 			 * @param {number} scrollDirection - Scroll direction, negative number being up and positive being down.
 			 * @return {void}
 			 */
 			positionStickyHeader = function( header, scrollTop, scrollDirection ) {
 				var headerElement = header.element,
 					headerParent = header.parent,
 					headerHeight = header.height,
 					headerTop = parseInt( headerElement.css( 'top' ), 10 ),
 					maybeSticky = headerElement.hasClass( 'maybe-sticky' ),
 					isSticky = headerElement.hasClass( 'is-sticky' ),
 					isInView = headerElement.hasClass( 'is-in-view' ),
 					isScrollingUp = ( -1 === scrollDirection );
 
 				// When scrolling down, gradually hide sticky header.
 				if ( ! isScrollingUp ) {
 					if ( isSticky ) {
 						headerTop = scrollTop;
 						headerElement
 							.removeClass( 'is-sticky' )
 							.css( {
 								top:   headerTop + 'px',
 								width: ''
 							} );
 					}
 					if ( isInView && scrollTop > headerTop + headerHeight ) {
 						headerElement.removeClass( 'is-in-view' );
 						headerParent.css( 'padding-top', '' );
 					}
 					return;
 				}
 
 				// Scrolling up.
 				if ( ! maybeSticky && scrollTop >= headerHeight ) {
 					maybeSticky = true;
 					headerElement.addClass( 'maybe-sticky' );
 				} else if ( 0 === scrollTop ) {
 					// Reset header in base position.
 					headerElement
 						.removeClass( 'maybe-sticky is-in-view is-sticky' )
 						.css( {
 							top:   '',
 							width: ''
 						} );
 					headerParent.css( 'padding-top', '' );
 					return;
 				}
 
 				if ( isInView && ! isSticky ) {
 					// Header is in the view but is not yet sticky.
 					if ( headerTop >= scrollTop ) {
 						// Header is fully visible.
 						headerElement
 							.addClass( 'is-sticky' )
 							.css( {
 								top:   parentContainer.css( 'top' ),
 								width: headerParent.outerWidth() + 'px'
 							} );
 					}
 				} else if ( maybeSticky && ! isInView ) {
 					// Header is out of the view.
 					headerElement
 						.addClass( 'is-in-view' )
 						.css( 'top', ( scrollTop - headerHeight ) + 'px' );
 					headerParent.css( 'padding-top', headerHeight + 'px' );
 				}
 			};
 		}());
 
 		// Previewed device bindings. (The api.previewedDevice property
 		// is how this Value was first introduced, but since it has moved to api.state.)
 		api.previewedDevice = api.state( 'previewedDevice' );
 
 		// Set the default device.
 		api.bind( 'ready', function() {
 			_.find( api.settings.previewableDevices, function( value, key ) {
 				if ( true === value['default'] ) {
 					api.previewedDevice.set( key );
 					return true;
 				}
 			} );
 		} );
 
 		// Set the toggled device.
 		footerActions.find( '.devices button' ).on( 'click', function( event ) {
 			api.previewedDevice.set( $( event.currentTarget ).data( 'device' ) );
 		});
 
 		// Bind device changes.
 		api.previewedDevice.bind( function( newDevice ) {
 			var overlay = $( '.wp-full-overlay' ),
 				devices = '';
 
 			footerActions.find( '.devices button' )
 				.removeClass( 'active' )
 				.attr( 'aria-pressed', false );
 
 			footerActions.find( '.devices .preview-' + newDevice )
 				.addClass( 'active' )
 				.attr( 'aria-pressed', true );
 
 			$.each( api.settings.previewableDevices, function( device ) {
 				devices += ' preview-' + device;
 			} );
 
 			overlay
 				.removeClass( devices )
 				.addClass( 'preview-' + newDevice );
 		} );
 
 		// Bind site title display to the corresponding field.
 		if ( title.length ) {
 			api( 'blogname', function( setting ) {
 				var updateTitle = function() {
 					var blogTitle = setting() || '';
 					title.text( blogTitle.toString().trim() || api.l10n.untitledBlogName );
 				};
 				setting.bind( updateTitle );
 				updateTitle();
 			} );
 		}
 
 		/*
 		 * Create a postMessage connection with a parent frame,
 		 * in case the Customizer frame was opened with the Customize loader.
 		 *
 		 * @see wp.customize.Loader
 		 */
 		parent = new api.Messenger({
 			url: api.settings.url.parent,
 			channel: 'loader'
 		});
 
 		// Handle exiting of Customizer.
 		(function() {
 			var isInsideIframe = false;
 
 			function isCleanState() {
 				var defaultChangesetStatus;
 
 				/*
 				 * Handle special case of previewing theme switch since some settings (for nav menus and widgets)
 				 * are pre-dirty and non-active themes can only ever be auto-drafts.
 				 */
 				if ( ! api.state( 'activated' ).get() ) {
 					return 0 === api._latestRevision;
 				}
 
 				// Dirty if the changeset status has been changed but not saved yet.
 				defaultChangesetStatus = api.state( 'changesetStatus' ).get();
 				if ( '' === defaultChangesetStatus || 'auto-draft' === defaultChangesetStatus ) {
 					defaultChangesetStatus = 'publish';
 				}
 				if ( api.state( 'selectedChangesetStatus' ).get() !== defaultChangesetStatus ) {
 					return false;
 				}
 
 				// Dirty if scheduled but the changeset date hasn't been saved yet.
 				if ( 'future' === api.state( 'selectedChangesetStatus' ).get() && api.state( 'selectedChangesetDate' ).get() !== api.state( 'changesetDate' ).get() ) {
 					return false;
 				}
 
 				return api.state( 'saved' ).get() && 'auto-draft' !== api.state( 'changesetStatus' ).get();
 			}
 
 			/*
 			 * If we receive a 'back' event, we're inside an iframe.
 			 * Send any clicks to the 'Return' link to the parent page.
 			 */
 			parent.bind( 'back', function() {
 				isInsideIframe = true;
 			});
 
 			function startPromptingBeforeUnload() {
 				api.unbind( 'change', startPromptingBeforeUnload );
 				api.state( 'selectedChangesetStatus' ).unbind( startPromptingBeforeUnload );
 				api.state( 'selectedChangesetDate' ).unbind( startPromptingBeforeUnload );
 
 				// Prompt user with AYS dialog if leaving the Customizer with unsaved changes.
 				$( window ).on( 'beforeunload.customize-confirm', function() {
 					if ( ! isCleanState() && ! api.state( 'changesetLocked' ).get() ) {
 						setTimeout( function() {
 							overlay.removeClass( 'customize-loading' );
 						}, 1 );
 						return api.l10n.saveAlert;
 					}
 				});
 			}
 			api.bind( 'change', startPromptingBeforeUnload );
 			api.state( 'selectedChangesetStatus' ).bind( startPromptingBeforeUnload );
 			api.state( 'selectedChangesetDate' ).bind( startPromptingBeforeUnload );
 
 			function requestClose() {
 				var clearedToClose = $.Deferred(), dismissAutoSave = false, dismissLock = false;
 
 				if ( isCleanState() ) {
 					dismissLock = true;
 				} else if ( confirm( api.l10n.saveAlert ) ) {
 
 					dismissLock = true;
 
 					// Mark all settings as clean to prevent another call to requestChangesetUpdate.
 					api.each( function( setting ) {
 						setting._dirty = false;
 					});
 					$( document ).off( 'visibilitychange.wp-customize-changeset-update' );
 					$( window ).off( 'beforeunload.wp-customize-changeset-update' );
 
 					closeBtn.css( 'cursor', 'progress' );
 					if ( '' !== api.state( 'changesetStatus' ).get() ) {
 						dismissAutoSave = true;
 					}
 				} else {
 					clearedToClose.reject();
 				}
 
 				if ( dismissLock || dismissAutoSave ) {
 					wp.ajax.send( 'customize_dismiss_autosave_or_lock', {
 						timeout: 500, // Don't wait too long.
 						data: {
 							wp_customize: 'on',
 							customize_theme: api.settings.theme.stylesheet,
 							customize_changeset_uuid: api.settings.changeset.uuid,
 							nonce: api.settings.nonce.dismiss_autosave_or_lock,
 							dismiss_autosave: dismissAutoSave,
 							dismiss_lock: dismissLock
 						}
 					} ).always( function() {
 						clearedToClose.resolve();
 					} );
 				}
 
 				return clearedToClose.promise();
 			}
 
 			parent.bind( 'confirm-close', function() {
 				requestClose().done( function() {
 					parent.send( 'confirmed-close', true );
 				} ).fail( function() {
 					parent.send( 'confirmed-close', false );
 				} );
 			} );
 
 			closeBtn.on( 'click.customize-controls-close', function( event ) {
 				event.preventDefault();
 				if ( isInsideIframe ) {
 					parent.send( 'close' ); // See confirm-close logic above.
 				} else {
 					requestClose().done( function() {
 						$( window ).off( 'beforeunload.customize-confirm' );
 						window.location.href = closeBtn.prop( 'href' );
 					} );
 				}
 			});
 		})();
 
 		// Pass events through to the parent.
 		$.each( [ 'saved', 'change' ], function ( i, event ) {
 			api.bind( event, function() {
 				parent.send( event );
 			});
 		} );
 
 		// Pass titles to the parent.
 		api.bind( 'title', function( newTitle ) {
 			parent.send( 'title', newTitle );
 		});
 
 		if ( api.settings.changeset.branching ) {
 			parent.send( 'changeset-uuid', api.settings.changeset.uuid );
 		}
 
 		// Initialize the connection with the parent frame.
 		parent.send( 'ready' );
 
 		// Control visibility for default controls.
 		$.each({
 			'background_image': {
 				controls: [ 'background_preset', 'background_position', 'background_size', 'background_repeat', 'background_attachment' ],
 				callback: function( to ) { return !! to; }
 			},
 			'show_on_front': {
 				controls: [ 'page_on_front', 'page_for_posts' ],
 				callback: function( to ) { return 'page' === to; }
 			},
 			'header_textcolor': {
 				controls: [ 'header_textcolor' ],
 				callback: function( to ) { return 'blank' !== to; }
 			}
 		}, function( settingId, o ) {
 			api( settingId, function( setting ) {
 				$.each( o.controls, function( i, controlId ) {
 					api.control( controlId, function( control ) {
 						var visibility = function( to ) {
 							control.container.toggle( o.callback( to ) );
 						};
 
 						visibility( setting.get() );
 						setting.bind( visibility );
 					});
 				});
 			});
 		});
 
 		api.control( 'background_preset', function( control ) {
 			var visibility, defaultValues, values, toggleVisibility, updateSettings, preset;
 
 			visibility = { // position, size, repeat, attachment.
 				'default': [ false, false, false, false ],
 				'fill': [ true, false, false, false ],
 				'fit': [ true, false, true, false ],
 				'repeat': [ true, false, false, true ],
 				'custom': [ true, true, true, true ]
 			};
 
 			defaultValues = [
 				_wpCustomizeBackground.defaults['default-position-x'],
 				_wpCustomizeBackground.defaults['default-position-y'],
 				_wpCustomizeBackground.defaults['default-size'],
 				_wpCustomizeBackground.defaults['default-repeat'],
 				_wpCustomizeBackground.defaults['default-attachment']
 			];
 
 			values = { // position_x, position_y, size, repeat, attachment.
 				'default': defaultValues,
 				'fill': [ 'left', 'top', 'cover', 'no-repeat', 'fixed' ],
 				'fit': [ 'left', 'top', 'contain', 'no-repeat', 'fixed' ],
 				'repeat': [ 'left', 'top', 'auto', 'repeat', 'scroll' ]
 			};
 
 			// @todo These should actually toggle the active state,
 			// but without the preview overriding the state in data.activeControls.
 			toggleVisibility = function( preset ) {
 				_.each( [ 'background_position', 'background_size', 'background_repeat', 'background_attachment' ], function( controlId, i ) {
 					var control = api.control( controlId );
 					if ( control ) {
 						control.container.toggle( visibility[ preset ][ i ] );
 					}
 				} );
 			};
 
 			updateSettings = function( preset ) {
 				_.each( [ 'background_position_x', 'background_position_y', 'background_size', 'background_repeat', 'background_attachment' ], function( settingId, i ) {
 					var setting = api( settingId );
 					if ( setting ) {
 						setting.set( values[ preset ][ i ] );
 					}
 				} );
 			};
 
 			preset = control.setting.get();
 			toggleVisibility( preset );
 
 			control.setting.bind( 'change', function( preset ) {
 				toggleVisibility( preset );
 				if ( 'custom' !== preset ) {
 					updateSettings( preset );
 				}
 			} );
 		} );
 
 		api.control( 'background_repeat', function( control ) {
 			control.elements[0].unsync( api( 'background_repeat' ) );
 
 			control.element = new api.Element( control.container.find( 'input' ) );
 			control.element.set( 'no-repeat' !== control.setting() );
 
 			control.element.bind( function( to ) {
 				control.setting.set( to ? 'repeat' : 'no-repeat' );
 			} );
 
 			control.setting.bind( function( to ) {
 				control.element.set( 'no-repeat' !== to );
 			} );
 		} );
 
 		api.control( 'background_attachment', function( control ) {
 			control.elements[0].unsync( api( 'background_attachment' ) );
 
 			control.element = new api.Element( control.container.find( 'input' ) );
 			control.element.set( 'fixed' !== control.setting() );
 
 			control.element.bind( function( to ) {
 				control.setting.set( to ? 'scroll' : 'fixed' );
 			} );
 
 			control.setting.bind( function( to ) {
 				control.element.set( 'fixed' !== to );
 			} );
 		} );
 
 		// Juggle the two controls that use header_textcolor.
 		api.control( 'display_header_text', function( control ) {
 			var last = '';
 
 			control.elements[0].unsync( api( 'header_textcolor' ) );
 
 			control.element = new api.Element( control.container.find('input') );
 			control.element.set( 'blank' !== control.setting() );
 
 			control.element.bind( function( to ) {
 				if ( ! to ) {
 					last = api( 'header_textcolor' ).get();
 				}
 
 				control.setting.set( to ? last : 'blank' );
 			});
 
 			control.setting.bind( function( to ) {
 				control.element.set( 'blank' !== to );
 			});
 		});
 
 		// Add behaviors to the static front page controls.
 		api( 'show_on_front', 'page_on_front', 'page_for_posts', function( showOnFront, pageOnFront, pageForPosts ) {
 			var handleChange = function() {
 				var setting = this, pageOnFrontId, pageForPostsId, errorCode = 'show_on_front_page_collision';
 				pageOnFrontId = parseInt( pageOnFront(), 10 );
 				pageForPostsId = parseInt( pageForPosts(), 10 );
 
 				if ( 'page' === showOnFront() ) {
 
 					// Change previewed URL to the homepage when changing the page_on_front.
 					if ( setting === pageOnFront && pageOnFrontId > 0 ) {
 						api.previewer.previewUrl.set( api.settings.url.home );
 					}
 
 					// Change the previewed URL to the selected page when changing the page_for_posts.
 					if ( setting === pageForPosts && pageForPostsId > 0 ) {
 						api.previewer.previewUrl.set( api.settings.url.home + '?page_id=' + pageForPostsId );
 					}
 				}
 
 				// Toggle notification when the homepage and posts page are both set and the same.
 				if ( 'page' === showOnFront() && pageOnFrontId && pageForPostsId && pageOnFrontId === pageForPostsId ) {
 					showOnFront.notifications.add( new api.Notification( errorCode, {
 						type: 'error',
 						message: api.l10n.pageOnFrontError
 					} ) );
 				} else {
 					showOnFront.notifications.remove( errorCode );
 				}
 			};
 			showOnFront.bind( handleChange );
 			pageOnFront.bind( handleChange );
 			pageForPosts.bind( handleChange );
 			handleChange.call( showOnFront, showOnFront() ); // Make sure initial notification is added after loading existing changeset.
 
 			// Move notifications container to the bottom.
 			api.control( 'show_on_front', function( showOnFrontControl ) {
 				showOnFrontControl.deferred.embedded.done( function() {
 					showOnFrontControl.container.append( showOnFrontControl.getNotificationsContainerElement() );
 				});
 			});
 		});
 
 		// Add code editor for Custom CSS.
 		(function() {
 			var sectionReady = $.Deferred();
 
 			api.section( 'custom_css', function( section ) {
 				section.deferred.embedded.done( function() {
 					if ( section.expanded() ) {
 						sectionReady.resolve( section );
 					} else {
 						section.expanded.bind( function( isExpanded ) {
 							if ( isExpanded ) {
 								sectionReady.resolve( section );
 							}
 						} );
 					}
 				});
 			});
 
 			// Set up the section description behaviors.
 			sectionReady.done( function setupSectionDescription( section ) {
 				var control = api.control( 'custom_css' );
 
 				// Hide redundant label for visual users.
 				control.container.find( '.customize-control-title:first' ).addClass( 'screen-reader-text' );
 
 				// Close the section description when clicking the close button.
 				section.container.find( '.section-description-buttons .section-description-close' ).on( 'click', function() {
 					section.container.find( '.section-meta .customize-section-description:first' )
 						.removeClass( 'open' )
 						.slideUp();
 
 					section.container.find( '.customize-help-toggle' )
 						.attr( 'aria-expanded', 'false' )
 						.focus(); // Avoid focus loss.
 				});
 
 				// Reveal help text if setting is empty.
 				if ( control && ! control.setting.get() ) {
 					section.container.find( '.section-meta .customize-section-description:first' )
 						.addClass( 'open' )
 						.show()
 						.trigger( 'toggled' );
 
 					section.container.find( '.customize-help-toggle' ).attr( 'aria-expanded', 'true' );
 				}
 			});
 		})();
 
 		// Toggle visibility of Header Video notice when active state change.
 		api.control( 'header_video', function( headerVideoControl ) {
 			headerVideoControl.deferred.embedded.done( function() {
 				var toggleNotice = function() {
 					var section = api.section( headerVideoControl.section() ), noticeCode = 'video_header_not_available';
 					if ( ! section ) {
 						return;
 					}
 					if ( headerVideoControl.active.get() ) {
 						section.notifications.remove( noticeCode );
 					} else {
 						section.notifications.add( new api.Notification( noticeCode, {
 							type: 'info',
 							message: api.l10n.videoHeaderNotice
 						} ) );
 					}
 				};
 				toggleNotice();
 				headerVideoControl.active.bind( toggleNotice );
 			} );
 		} );
 
 		// Update the setting validities.
 		api.previewer.bind( 'selective-refresh-setting-validities', function handleSelectiveRefreshedSettingValidities( settingValidities ) {
 			api._handleSettingValidities( {
 				settingValidities: settingValidities,
 				focusInvalidControl: false
 			} );
 		} );
 
 		// Focus on the control that is associated with the given setting.
 		api.previewer.bind( 'focus-control-for-setting', function( settingId ) {
 			var matchedControls = [];
 			api.control.each( function( control ) {
 				var settingIds = _.pluck( control.settings, 'id' );
 				if ( -1 !== _.indexOf( settingIds, settingId ) ) {
 					matchedControls.push( control );
 				}
 			} );
 
 			// Focus on the matched control with the lowest priority (appearing higher).
 			if ( matchedControls.length ) {
 				matchedControls.sort( function( a, b ) {
 					return a.priority() - b.priority();
 				} );
 				matchedControls[0].focus();
 			}
 		} );
 
 		// Refresh the preview when it requests.
 		api.previewer.bind( 'refresh', function() {
 			api.previewer.refresh();
 		});
 
 		// Update the edit shortcut visibility state.
 		api.state( 'paneVisible' ).bind( function( isPaneVisible ) {
 			var isMobileScreen;
 			if ( window.matchMedia ) {
 				isMobileScreen = window.matchMedia( 'screen and ( max-width: 640px )' ).matches;
 			} else {
 				isMobileScreen = $( window ).width() <= 640;
 			}
 			api.state( 'editShortcutVisibility' ).set( isPaneVisible || isMobileScreen ? 'visible' : 'hidden' );
 		} );
 		if ( window.matchMedia ) {
 			window.matchMedia( 'screen and ( max-width: 640px )' ).addListener( function() {
 				var state = api.state( 'paneVisible' );
 				state.callbacks.fireWith( state, [ state.get(), state.get() ] );
 			} );
 		}
 		api.previewer.bind( 'edit-shortcut-visibility', function( visibility ) {
 			api.state( 'editShortcutVisibility' ).set( visibility );
 		} );
 		api.state( 'editShortcutVisibility' ).bind( function( visibility ) {
 			api.previewer.send( 'edit-shortcut-visibility', visibility );
 		} );
 
 		// Autosave changeset.
 		function startAutosaving() {
 			var timeoutId, updateChangesetWithReschedule, scheduleChangesetUpdate, updatePending = false;
 
 			api.unbind( 'change', startAutosaving ); // Ensure startAutosaving only fires once.
 
 			function onChangeSaved( isSaved ) {
 				if ( ! isSaved && ! api.settings.changeset.autosaved ) {
 					api.settings.changeset.autosaved = true; // Once a change is made then autosaving kicks in.
 					api.previewer.send( 'autosaving' );
 				}
 			}
 			api.state( 'saved' ).bind( onChangeSaved );
 			onChangeSaved( api.state( 'saved' ).get() );
 
 			/**
 			 * Request changeset update and then re-schedule the next changeset update time.
 			 *
 			 * @since 4.7.0
 			 * @private
 			 */
 			updateChangesetWithReschedule = function() {
 				if ( ! updatePending ) {
 					updatePending = true;
 					api.requestChangesetUpdate( {}, { autosave: true } ).always( function() {
 						updatePending = false;
 					} );
 				}
 				scheduleChangesetUpdate();
 			};
 
 			/**
 			 * Schedule changeset update.
 			 *
 			 * @since 4.7.0
 			 * @private
 			 */
 			scheduleChangesetUpdate = function() {
 				clearTimeout( timeoutId );
 				timeoutId = setTimeout( function() {
 					updateChangesetWithReschedule();
 				}, api.settings.timeouts.changesetAutoSave );
 			};
 
 			// Start auto-save interval for updating changeset.
 			scheduleChangesetUpdate();
 
 			// Save changeset when focus removed from window.
 			$( document ).on( 'visibilitychange.wp-customize-changeset-update', function() {
 				if ( document.hidden ) {
 					updateChangesetWithReschedule();
 				}
 			} );
 
 			// Save changeset before unloading window.
 			$( window ).on( 'beforeunload.wp-customize-changeset-update', function() {
 				updateChangesetWithReschedule();
 			} );
 		}
 		api.bind( 'change', startAutosaving );
 
 		// Make sure TinyMCE dialogs appear above Customizer UI.
 		$( document ).one( 'tinymce-editor-setup', function() {
 			if ( window.tinymce.ui.FloatPanel && ( ! window.tinymce.ui.FloatPanel.zIndex || window.tinymce.ui.FloatPanel.zIndex < 500001 ) ) {
 				window.tinymce.ui.FloatPanel.zIndex = 500001;
 			}
 		} );
 
 		body.addClass( 'ready' );
 		api.trigger( 'ready' );
 	});
 
 })( wp, jQuery );