diff -r 490d5cc509ed -r cf61fcea0001 wp/wp-admin/js/customize-nav-menus.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-admin/js/customize-nav-menus.js	Mon Oct 14 17:39:30 2019 +0200
@@ -0,0 +1,3449 @@
+/* global _wpCustomizeNavMenusSettings, wpNavMenu, console */
+( function( api, wp, $ ) {
+	'use strict';
+
+	/**
+	 * Set up wpNavMenu for drag and drop.
+	 */
+	wpNavMenu.originalInit = wpNavMenu.init;
+	wpNavMenu.options.menuItemDepthPerLevel = 20;
+	wpNavMenu.options.sortableItems         = '> .customize-control-nav_menu_item';
+	wpNavMenu.options.targetTolerance       = 10;
+	wpNavMenu.init = function() {
+		this.jQueryExtensions();
+	};
+
+	api.Menus = api.Menus || {};
+
+	// Link settings.
+	api.Menus.data = {
+		itemTypes: [],
+		l10n: {},
+		settingTransport: 'refresh',
+		phpIntMax: 0,
+		defaultSettingValues: {
+			nav_menu: {},
+			nav_menu_item: {}
+		},
+		locationSlugMappedToName: {}
+	};
+	if ( 'undefined' !== typeof _wpCustomizeNavMenusSettings ) {
+		$.extend( api.Menus.data, _wpCustomizeNavMenusSettings );
+	}
+
+	/**
+	 * Newly-created Nav Menus and Nav Menu Items have negative integer IDs which
+	 * serve as placeholders until Save & Publish happens.
+	 *
+	 * @return {number}
+	 */
+	api.Menus.generatePlaceholderAutoIncrementId = function() {
+		return -Math.ceil( api.Menus.data.phpIntMax * Math.random() );
+	};
+
+	/**
+	 * wp.customize.Menus.AvailableItemModel
+	 *
+	 * A single available menu item model. See PHP's WP_Customize_Nav_Menu_Item_Setting class.
+	 *
+	 * @constructor
+	 * @augments Backbone.Model
+	 */
+	api.Menus.AvailableItemModel = Backbone.Model.extend( $.extend(
+		{
+			id: null // This is only used by Backbone.
+		},
+		api.Menus.data.defaultSettingValues.nav_menu_item
+	) );
+
+	/**
+	 * wp.customize.Menus.AvailableItemCollection
+	 *
+	 * Collection for available menu item models.
+	 *
+	 * @constructor
+	 * @augments Backbone.Model
+	 */
+	api.Menus.AvailableItemCollection = Backbone.Collection.extend({
+		model: api.Menus.AvailableItemModel,
+
+		sort_key: 'order',
+
+		comparator: function( item ) {
+			return -item.get( this.sort_key );
+		},
+
+		sortByField: function( fieldName ) {
+			this.sort_key = fieldName;
+			this.sort();
+		}
+	});
+	api.Menus.availableMenuItems = new api.Menus.AvailableItemCollection( api.Menus.data.availableMenuItems );
+
+	/**
+	 * Insert a new `auto-draft` post.
+	 *
+	 * @since 4.7.0
+	 * @access public
+	 *
+	 * @param {object} params - Parameters for the draft post to create.
+	 * @param {string} params.post_type - Post type to add.
+	 * @param {string} params.post_title - Post title to use.
+	 * @return {jQuery.promise} Promise resolved with the added post.
+	 */
+	api.Menus.insertAutoDraftPost = function insertAutoDraftPost( params ) {
+		var request, deferred = $.Deferred();
+
+		request = wp.ajax.post( 'customize-nav-menus-insert-auto-draft', {
+			'customize-menus-nonce': api.settings.nonce['customize-menus'],
+			'wp_customize': 'on',
+			'customize_changeset_uuid': api.settings.changeset.uuid,
+			'params': params
+		} );
+
+		request.done( function( response ) {
+			if ( response.post_id ) {
+				api( 'nav_menus_created_posts' ).set(
+					api( 'nav_menus_created_posts' ).get().concat( [ response.post_id ] )
+				);
+
+				if ( 'page' === params.post_type ) {
+
+					// Activate static front page controls as this could be the first page created.
+					if ( api.section.has( 'static_front_page' ) ) {
+						api.section( 'static_front_page' ).activate();
+					}
+
+					// Add new page to dropdown-pages controls.
+					api.control.each( function( control ) {
+						var select;
+						if ( 'dropdown-pages' === control.params.type ) {
+							select = control.container.find( 'select[name^="_customize-dropdown-pages-"]' );
+							select.append( new Option( params.post_title, response.post_id ) );
+						}
+					} );
+				}
+				deferred.resolve( response );
+			}
+		} );
+
+		request.fail( function( response ) {
+			var error = response || '';
+
+			if ( 'undefined' !== typeof response.message ) {
+				error = response.message;
+			}
+
+			console.error( error );
+			deferred.rejectWith( error );
+		} );
+
+		return deferred.promise();
+	};
+
+	/**
+	 * wp.customize.Menus.AvailableMenuItemsPanelView
+	 *
+	 * View class for the available menu items panel.
+	 *
+	 * @constructor
+	 * @augments wp.Backbone.View
+	 * @augments Backbone.View
+	 */
+	api.Menus.AvailableMenuItemsPanelView = wp.Backbone.View.extend({
+
+		el: '#available-menu-items',
+
+		events: {
+			'input #menu-items-search': 'debounceSearch',
+			'keyup #menu-items-search': 'debounceSearch',
+			'focus .menu-item-tpl': 'focus',
+			'click .menu-item-tpl': '_submit',
+			'click #custom-menu-item-submit': '_submitLink',
+			'keypress #custom-menu-item-name': '_submitLink',
+			'click .new-content-item .add-content': '_submitNew',
+			'keypress .create-item-input': '_submitNew',
+			'keydown': 'keyboardAccessible'
+		},
+
+		// Cache current selected menu item.
+		selected: null,
+
+		// Cache menu control that opened the panel.
+		currentMenuControl: null,
+		debounceSearch: null,
+		$search: null,
+		$clearResults: null,
+		searchTerm: '',
+		rendered: false,
+		pages: {},
+		sectionContent: '',
+		loading: false,
+		addingNew: false,
+
+		initialize: function() {
+			var self = this;
+
+			if ( ! api.panel.has( 'nav_menus' ) ) {
+				return;
+			}
+
+			this.$search = $( '#menu-items-search' );
+			this.$clearResults = this.$el.find( '.clear-results' );
+			this.sectionContent = this.$el.find( '.available-menu-items-list' );
+
+			this.debounceSearch = _.debounce( self.search, 500 );
+
+			_.bindAll( this, 'close' );
+
+			// If the available menu items panel is open and the customize controls are
+			// interacted with (other than an item being deleted), then close the
+			// available menu items panel. Also close on back button click.
+			$( '#customize-controls, .customize-section-back' ).on( 'click keydown', function( e ) {
+				var isDeleteBtn = $( e.target ).is( '.item-delete, .item-delete *' ),
+					isAddNewBtn = $( e.target ).is( '.add-new-menu-item, .add-new-menu-item *' );
+				if ( $( 'body' ).hasClass( 'adding-menu-items' ) && ! isDeleteBtn && ! isAddNewBtn ) {
+					self.close();
+				}
+			} );
+
+			// Clear the search results and trigger a `keyup` event to fire a new search.
+			this.$clearResults.on( 'click', function() {
+				self.$search.val( '' ).focus().trigger( 'keyup' );
+			} );
+
+			this.$el.on( 'input', '#custom-menu-item-name.invalid, #custom-menu-item-url.invalid', function() {
+				$( this ).removeClass( 'invalid' );
+			});
+
+			// Load available items if it looks like we'll need them.
+			api.panel( 'nav_menus' ).container.bind( 'expanded', function() {
+				if ( ! self.rendered ) {
+					self.initList();
+					self.rendered = true;
+				}
+			});
+
+			// Load more items.
+			this.sectionContent.scroll( function() {
+				var totalHeight = self.$el.find( '.accordion-section.open .available-menu-items-list' ).prop( 'scrollHeight' ),
+					visibleHeight = self.$el.find( '.accordion-section.open' ).height();
+
+				if ( ! self.loading && $( this ).scrollTop() > 3 / 4 * totalHeight - visibleHeight ) {
+					var type = $( this ).data( 'type' ),
+						object = $( this ).data( 'object' );
+
+					if ( 'search' === type ) {
+						if ( self.searchTerm ) {
+							self.doSearch( self.pages.search );
+						}
+					} else {
+						self.loadItems( [
+							{ type: type, object: object }
+						] );
+					}
+				}
+			});
+
+			// Close the panel if the URL in the preview changes
+			api.previewer.bind( 'url', this.close );
+
+			self.delegateEvents();
+		},
+
+		// Search input change handler.
+		search: function( event ) {
+			var $searchSection = $( '#available-menu-items-search' ),
+				$otherSections = $( '#available-menu-items .accordion-section' ).not( $searchSection );
+
+			if ( ! event ) {
+				return;
+			}
+
+			if ( this.searchTerm === event.target.value ) {
+				return;
+			}
+
+			if ( '' !== event.target.value && ! $searchSection.hasClass( 'open' ) ) {
+				$otherSections.fadeOut( 100 );
+				$searchSection.find( '.accordion-section-content' ).slideDown( 'fast' );
+				$searchSection.addClass( 'open' );
+				this.$clearResults.addClass( 'is-visible' );
+			} else if ( '' === event.target.value ) {
+				$searchSection.removeClass( 'open' );
+				$otherSections.show();
+				this.$clearResults.removeClass( 'is-visible' );
+			}
+
+			this.searchTerm = event.target.value;
+			this.pages.search = 1;
+			this.doSearch( 1 );
+		},
+
+		// Get search results.
+		doSearch: function( page ) {
+			var self = this, params,
+				$section = $( '#available-menu-items-search' ),
+				$content = $section.find( '.accordion-section-content' ),
+				itemTemplate = wp.template( 'available-menu-item' );
+
+			if ( self.currentRequest ) {
+				self.currentRequest.abort();
+			}
+
+			if ( page < 0 ) {
+				return;
+			} else if ( page > 1 ) {
+				$section.addClass( 'loading-more' );
+				$content.attr( 'aria-busy', 'true' );
+				wp.a11y.speak( api.Menus.data.l10n.itemsLoadingMore );
+			} else if ( '' === self.searchTerm ) {
+				$content.html( '' );
+				wp.a11y.speak( '' );
+				return;
+			}
+
+			$section.addClass( 'loading' );
+			self.loading = true;
+
+			params = api.previewer.query( { excludeCustomizedSaved: true } );
+			_.extend( params, {
+				'customize-menus-nonce': api.settings.nonce['customize-menus'],
+				'wp_customize': 'on',
+				'search': self.searchTerm,
+				'page': page
+			} );
+
+			self.currentRequest = wp.ajax.post( 'search-available-menu-items-customizer', params );
+
+			self.currentRequest.done(function( data ) {
+				var items;
+				if ( 1 === page ) {
+					// Clear previous results as it's a new search.
+					$content.empty();
+				}
+				$section.removeClass( 'loading loading-more' );
+				$content.attr( 'aria-busy', 'false' );
+				$section.addClass( 'open' );
+				self.loading = false;
+				items = new api.Menus.AvailableItemCollection( data.items );
+				self.collection.add( items.models );
+				items.each( function( menuItem ) {
+					$content.append( itemTemplate( menuItem.attributes ) );
+				} );
+				if ( 20 > items.length ) {
+					self.pages.search = -1; // Up to 20 posts and 20 terms in results, if <20, no more results for either.
+				} else {
+					self.pages.search = self.pages.search + 1;
+				}
+				if ( items && page > 1 ) {
+					wp.a11y.speak( api.Menus.data.l10n.itemsFoundMore.replace( '%d', items.length ) );
+				} else if ( items && page === 1 ) {
+					wp.a11y.speak( api.Menus.data.l10n.itemsFound.replace( '%d', items.length ) );
+				}
+			});
+
+			self.currentRequest.fail(function( data ) {
+				// data.message may be undefined, for example when typing slow and the request is aborted.
+				if ( data.message ) {
+					$content.empty().append( $( '<li class="nothing-found"></li>' ).text( data.message ) );
+					wp.a11y.speak( data.message );
+				}
+				self.pages.search = -1;
+			});
+
+			self.currentRequest.always(function() {
+				$section.removeClass( 'loading loading-more' );
+				$content.attr( 'aria-busy', 'false' );
+				self.loading = false;
+				self.currentRequest = null;
+			});
+		},
+
+		// Render the individual items.
+		initList: function() {
+			var self = this;
+
+			// Render the template for each item by type.
+			_.each( api.Menus.data.itemTypes, function( itemType ) {
+				self.pages[ itemType.type + ':' + itemType.object ] = 0;
+			} );
+			self.loadItems( api.Menus.data.itemTypes );
+		},
+
+		/**
+		 * Load available nav menu items.
+		 *
+		 * @since 4.3.0
+		 * @since 4.7.0 Changed function signature to take list of item types instead of single type/object.
+		 * @access private
+		 *
+		 * @param {Array.<object>} itemTypes List of objects containing type and key.
+		 * @param {string} deprecated Formerly the object parameter.
+		 * @returns {void}
+		 */
+		loadItems: function( itemTypes, deprecated ) {
+			var self = this, _itemTypes, requestItemTypes = [], params, request, itemTemplate, availableMenuItemContainers = {};
+			itemTemplate = wp.template( 'available-menu-item' );
+
+			if ( _.isString( itemTypes ) && _.isString( deprecated ) ) {
+				_itemTypes = [ { type: itemTypes, object: deprecated } ];
+			} else {
+				_itemTypes = itemTypes;
+			}
+
+			_.each( _itemTypes, function( itemType ) {
+				var container, name = itemType.type + ':' + itemType.object;
+				if ( -1 === self.pages[ name ] ) {
+					return; // Skip types for which there are no more results.
+				}
+				container = $( '#available-menu-items-' + itemType.type + '-' + itemType.object );
+				container.find( '.accordion-section-title' ).addClass( 'loading' );
+				availableMenuItemContainers[ name ] = container;
+
+				requestItemTypes.push( {
+					object: itemType.object,
+					type: itemType.type,
+					page: self.pages[ name ]
+				} );
+			} );
+
+			if ( 0 === requestItemTypes.length ) {
+				return;
+			}
+
+			self.loading = true;
+
+			params = api.previewer.query( { excludeCustomizedSaved: true } );
+			_.extend( params, {
+				'customize-menus-nonce': api.settings.nonce['customize-menus'],
+				'wp_customize': 'on',
+				'item_types': requestItemTypes
+			} );
+
+			request = wp.ajax.post( 'load-available-menu-items-customizer', params );
+
+			request.done(function( data ) {
+				var typeInner;
+				_.each( data.items, function( typeItems, name ) {
+					if ( 0 === typeItems.length ) {
+						if ( 0 === self.pages[ name ] ) {
+							availableMenuItemContainers[ name ].find( '.accordion-section-title' )
+								.addClass( 'cannot-expand' )
+								.removeClass( 'loading' )
+								.find( '.accordion-section-title > button' )
+								.prop( 'tabIndex', -1 );
+						}
+						self.pages[ name ] = -1;
+						return;
+					} else if ( ( 'post_type:page' === name ) && ( ! availableMenuItemContainers[ name ].hasClass( 'open' ) ) ) {
+						availableMenuItemContainers[ name ].find( '.accordion-section-title > button' ).click();
+					}
+					typeItems = new api.Menus.AvailableItemCollection( typeItems ); // @todo Why is this collection created and then thrown away?
+					self.collection.add( typeItems.models );
+					typeInner = availableMenuItemContainers[ name ].find( '.available-menu-items-list' );
+					typeItems.each( function( menuItem ) {
+						typeInner.append( itemTemplate( menuItem.attributes ) );
+					} );
+					self.pages[ name ] += 1;
+				});
+			});
+			request.fail(function( data ) {
+				if ( typeof console !== 'undefined' && console.error ) {
+					console.error( data );
+				}
+			});
+			request.always(function() {
+				_.each( availableMenuItemContainers, function( container ) {
+					container.find( '.accordion-section-title' ).removeClass( 'loading' );
+				} );
+				self.loading = false;
+			});
+		},
+
+		// Adjust the height of each section of items to fit the screen.
+		itemSectionHeight: function() {
+			var sections, lists, totalHeight, accordionHeight, diff;
+			totalHeight = window.innerHeight;
+			sections = this.$el.find( '.accordion-section:not( #available-menu-items-search ) .accordion-section-content' );
+			lists = this.$el.find( '.accordion-section:not( #available-menu-items-search ) .available-menu-items-list:not(":only-child")' );
+			accordionHeight =  46 * ( 1 + sections.length ) + 14; // Magic numbers.
+			diff = totalHeight - accordionHeight;
+			if ( 120 < diff && 290 > diff ) {
+				sections.css( 'max-height', diff );
+				lists.css( 'max-height', ( diff - 60 ) );
+			}
+		},
+
+		// Highlights a menu item.
+		select: function( menuitemTpl ) {
+			this.selected = $( menuitemTpl );
+			this.selected.siblings( '.menu-item-tpl' ).removeClass( 'selected' );
+			this.selected.addClass( 'selected' );
+		},
+
+		// Highlights a menu item on focus.
+		focus: function( event ) {
+			this.select( $( event.currentTarget ) );
+		},
+
+		// Submit handler for keypress and click on menu item.
+		_submit: function( event ) {
+			// Only proceed with keypress if it is Enter or Spacebar
+			if ( 'keypress' === event.type && ( 13 !== event.which && 32 !== event.which ) ) {
+				return;
+			}
+
+			this.submit( $( event.currentTarget ) );
+		},
+
+		// Adds a selected menu item to the menu.
+		submit: function( menuitemTpl ) {
+			var menuitemId, menu_item;
+
+			if ( ! menuitemTpl ) {
+				menuitemTpl = this.selected;
+			}
+
+			if ( ! menuitemTpl || ! this.currentMenuControl ) {
+				return;
+			}
+
+			this.select( menuitemTpl );
+
+			menuitemId = $( this.selected ).data( 'menu-item-id' );
+			menu_item = this.collection.findWhere( { id: menuitemId } );
+			if ( ! menu_item ) {
+				return;
+			}
+
+			this.currentMenuControl.addItemToMenu( menu_item.attributes );
+
+			$( menuitemTpl ).find( '.menu-item-handle' ).addClass( 'item-added' );
+		},
+
+		// Submit handler for keypress and click on custom menu item.
+		_submitLink: function( event ) {
+			// Only proceed with keypress if it is Enter.
+			if ( 'keypress' === event.type && 13 !== event.which ) {
+				return;
+			}
+
+			this.submitLink();
+		},
+
+		// Adds the custom menu item to the menu.
+		submitLink: function() {
+			var menuItem,
+				itemName = $( '#custom-menu-item-name' ),
+				itemUrl = $( '#custom-menu-item-url' ),
+				urlRegex;
+
+			if ( ! this.currentMenuControl ) {
+				return;
+			}
+
+			/*
+			 * Allow URLs including:
+			 * - http://example.com/
+			 * - //example.com
+			 * - /directory/
+			 * - ?query-param
+			 * - #target
+			 * - mailto:foo@example.com
+			 *
+			 * Any further validation will be handled on the server when the setting is attempted to be saved,
+			 * so this pattern does not need to be complete.
+			 */
+			urlRegex = /^((\w+:)?\/\/\w.*|\w+:(?!\/\/$)|\/|\?|#)/;
+
+			if ( '' === itemName.val() ) {
+				itemName.addClass( 'invalid' );
+				return;
+			} else if ( ! urlRegex.test( itemUrl.val() ) ) {
+				itemUrl.addClass( 'invalid' );
+				return;
+			}
+
+			menuItem = {
+				'title': itemName.val(),
+				'url': itemUrl.val(),
+				'type': 'custom',
+				'type_label': api.Menus.data.l10n.custom_label,
+				'object': 'custom'
+			};
+
+			this.currentMenuControl.addItemToMenu( menuItem );
+
+			// Reset the custom link form.
+			itemUrl.val( 'http://' );
+			itemName.val( '' );
+		},
+
+		/**
+		 * Submit handler for keypress (enter) on field and click on button.
+		 *
+		 * @since 4.7.0
+		 * @private
+		 *
+		 * @param {jQuery.Event} event Event.
+		 * @returns {void}
+		 */
+		_submitNew: function( event ) {
+			var container;
+
+			// Only proceed with keypress if it is Enter.
+			if ( 'keypress' === event.type && 13 !== event.which ) {
+				return;
+			}
+
+			if ( this.addingNew ) {
+				return;
+			}
+
+			container = $( event.target ).closest( '.accordion-section' );
+
+			this.submitNew( container );
+		},
+
+		/**
+		 * Creates a new object and adds an associated menu item to the menu.
+		 *
+		 * @since 4.7.0
+		 * @private
+		 *
+		 * @param {jQuery} container
+		 * @returns {void}
+		 */
+		submitNew: function( container ) {
+			var panel = this,
+				itemName = container.find( '.create-item-input' ),
+				title = itemName.val(),
+				dataContainer = container.find( '.available-menu-items-list' ),
+				itemType = dataContainer.data( 'type' ),
+				itemObject = dataContainer.data( 'object' ),
+				itemTypeLabel = dataContainer.data( 'type_label' ),
+				promise;
+
+			if ( ! this.currentMenuControl ) {
+				return;
+			}
+
+			// Only posts are supported currently.
+			if ( 'post_type' !== itemType ) {
+				return;
+			}
+
+			if ( '' === $.trim( itemName.val() ) ) {
+				itemName.addClass( 'invalid' );
+				itemName.focus();
+				return;
+			} else {
+				itemName.removeClass( 'invalid' );
+				container.find( '.accordion-section-title' ).addClass( 'loading' );
+			}
+
+			panel.addingNew = true;
+			itemName.attr( 'disabled', 'disabled' );
+			promise = api.Menus.insertAutoDraftPost( {
+				post_title: title,
+				post_type: itemObject
+			} );
+			promise.done( function( data ) {
+				var availableItem, $content, itemElement;
+				availableItem = new api.Menus.AvailableItemModel( {
+					'id': 'post-' + data.post_id, // Used for available menu item Backbone models.
+					'title': itemName.val(),
+					'type': itemType,
+					'type_label': itemTypeLabel,
+					'object': itemObject,
+					'object_id': data.post_id,
+					'url': data.url
+				} );
+
+				// Add new item to menu.
+				panel.currentMenuControl.addItemToMenu( availableItem.attributes );
+
+				// Add the new item to the list of available items.
+				api.Menus.availableMenuItemsPanel.collection.add( availableItem );
+				$content = container.find( '.available-menu-items-list' );
+				itemElement = $( wp.template( 'available-menu-item' )( availableItem.attributes ) );
+				itemElement.find( '.menu-item-handle:first' ).addClass( 'item-added' );
+				$content.prepend( itemElement );
+				$content.scrollTop();
+
+				// Reset the create content form.
+				itemName.val( '' ).removeAttr( 'disabled' );
+				panel.addingNew = false;
+				container.find( '.accordion-section-title' ).removeClass( 'loading' );
+			} );
+		},
+
+		// Opens the panel.
+		open: function( menuControl ) {
+			var panel = this, close;
+
+			this.currentMenuControl = menuControl;
+
+			this.itemSectionHeight();
+
+			if ( api.section.has( 'publish_settings' ) ) {
+				api.section( 'publish_settings' ).collapse();
+			}
+
+			$( 'body' ).addClass( 'adding-menu-items' );
+
+			close = function() {
+				panel.close();
+				$( this ).off( 'click', close );
+			};
+			$( '#customize-preview' ).on( 'click', close );
+
+			// Collapse all controls.
+			_( this.currentMenuControl.getMenuItemControls() ).each( function( control ) {
+				control.collapseForm();
+			} );
+
+			this.$el.find( '.selected' ).removeClass( 'selected' );
+
+			this.$search.focus();
+		},
+
+		// Closes the panel
+		close: function( options ) {
+			options = options || {};
+
+			if ( options.returnFocus && this.currentMenuControl ) {
+				this.currentMenuControl.container.find( '.add-new-menu-item' ).focus();
+			}
+
+			this.currentMenuControl = null;
+			this.selected = null;
+
+			$( 'body' ).removeClass( 'adding-menu-items' );
+			$( '#available-menu-items .menu-item-handle.item-added' ).removeClass( 'item-added' );
+
+			this.$search.val( '' ).trigger( 'keyup' );
+		},
+
+		// Add a few keyboard enhancements to the panel.
+		keyboardAccessible: function( event ) {
+			var isEnter = ( 13 === event.which ),
+				isEsc = ( 27 === event.which ),
+				isBackTab = ( 9 === event.which && event.shiftKey ),
+				isSearchFocused = $( event.target ).is( this.$search );
+
+			// If enter pressed but nothing entered, don't do anything
+			if ( isEnter && ! this.$search.val() ) {
+				return;
+			}
+
+			if ( isSearchFocused && isBackTab ) {
+				this.currentMenuControl.container.find( '.add-new-menu-item' ).focus();
+				event.preventDefault(); // Avoid additional back-tab.
+			} else if ( isEsc ) {
+				this.close( { returnFocus: true } );
+			}
+		}
+	});
+
+	/**
+	 * wp.customize.Menus.MenusPanel
+	 *
+	 * Customizer panel for menus. This is used only for screen options management.
+	 * Note that 'menus' must match the WP_Customize_Menu_Panel::$type.
+	 *
+	 * @constructor
+	 * @augments wp.customize.Panel
+	 */
+	api.Menus.MenusPanel = api.Panel.extend({
+
+		attachEvents: function() {
+			api.Panel.prototype.attachEvents.call( this );
+
+			var panel = this,
+				panelMeta = panel.container.find( '.panel-meta' ),
+				help = panelMeta.find( '.customize-help-toggle' ),
+				content = panelMeta.find( '.customize-panel-description' ),
+				options = $( '#screen-options-wrap' ),
+				button = panelMeta.find( '.customize-screen-options-toggle' );
+			button.on( 'click keydown', function( event ) {
+				if ( api.utils.isKeydownButNotEnterEvent( event ) ) {
+					return;
+				}
+				event.preventDefault();
+
+				// Hide description
+				if ( content.not( ':hidden' ) ) {
+					content.slideUp( 'fast' );
+					help.attr( 'aria-expanded', 'false' );
+				}
+
+				if ( 'true' === button.attr( 'aria-expanded' ) ) {
+					button.attr( 'aria-expanded', 'false' );
+					panelMeta.removeClass( 'open' );
+					panelMeta.removeClass( 'active-menu-screen-options' );
+					options.slideUp( 'fast' );
+				} else {
+					button.attr( 'aria-expanded', 'true' );
+					panelMeta.addClass( 'open' );
+					panelMeta.addClass( 'active-menu-screen-options' );
+					options.slideDown( 'fast' );
+				}
+
+				return false;
+			} );
+
+			// Help toggle
+			help.on( 'click keydown', function( event ) {
+				if ( api.utils.isKeydownButNotEnterEvent( event ) ) {
+					return;
+				}
+				event.preventDefault();
+
+				if ( 'true' === button.attr( 'aria-expanded' ) ) {
+					button.attr( 'aria-expanded', 'false' );
+					help.attr( 'aria-expanded', 'true' );
+					panelMeta.addClass( 'open' );
+					panelMeta.removeClass( 'active-menu-screen-options' );
+					options.slideUp( 'fast' );
+					content.slideDown( 'fast' );
+				}
+			} );
+		},
+
+		/**
+		 * Update field visibility when clicking on the field toggles.
+		 */
+		ready: function() {
+			var panel = this;
+			panel.container.find( '.hide-column-tog' ).click( function() {
+				panel.saveManageColumnsState();
+			});
+
+			// Inject additional heading into the menu locations section's head container.
+			api.section( 'menu_locations', function( section ) {
+				section.headContainer.prepend(
+					wp.template( 'nav-menu-locations-header' )( api.Menus.data )
+				);
+			} );
+		},
+
+		/**
+		 * Save hidden column states.
+		 *
+		 * @since 4.3.0
+		 * @private
+		 *
+		 * @returns {void}
+		 */
+		saveManageColumnsState: _.debounce( function() {
+			var panel = this;
+			if ( panel._updateHiddenColumnsRequest ) {
+				panel._updateHiddenColumnsRequest.abort();
+			}
+
+			panel._updateHiddenColumnsRequest = wp.ajax.post( 'hidden-columns', {
+				hidden: panel.hidden(),
+				screenoptionnonce: $( '#screenoptionnonce' ).val(),
+				page: 'nav-menus'
+			} );
+			panel._updateHiddenColumnsRequest.always( function() {
+				panel._updateHiddenColumnsRequest = null;
+			} );
+		}, 2000 ),
+
+		/**
+		 * @deprecated Since 4.7.0 now that the nav_menu sections are responsible for toggling the classes on their own containers.
+		 */
+		checked: function() {},
+
+		/**
+		 * @deprecated Since 4.7.0 now that the nav_menu sections are responsible for toggling the classes on their own containers.
+		 */
+		unchecked: function() {},
+
+		/**
+		 * Get hidden fields.
+		 *
+		 * @since 4.3.0
+		 * @private
+		 *
+		 * @returns {Array} Fields (columns) that are hidden.
+		 */
+		hidden: function() {
+			return $( '.hide-column-tog' ).not( ':checked' ).map( function() {
+				var id = this.id;
+				return id.substring( 0, id.length - 5 );
+			}).get().join( ',' );
+		}
+	} );
+
+	/**
+	 * wp.customize.Menus.MenuSection
+	 *
+	 * Customizer section for menus. This is used only for lazy-loading child controls.
+	 * Note that 'nav_menu' must match the WP_Customize_Menu_Section::$type.
+	 *
+	 * @constructor
+	 * @augments wp.customize.Section
+	 */
+	api.Menus.MenuSection = api.Section.extend({
+
+		/**
+		 * Initialize.
+		 *
+		 * @since 4.3.0
+		 *
+		 * @param {String} id
+		 * @param {Object} options
+		 */
+		initialize: function( id, options ) {
+			var section = this;
+			api.Section.prototype.initialize.call( section, id, options );
+			section.deferred.initSortables = $.Deferred();
+		},
+
+		/**
+		 * Ready.
+		 */
+		ready: function() {
+			var section = this, fieldActiveToggles, handleFieldActiveToggle;
+
+			if ( 'undefined' === typeof section.params.menu_id ) {
+				throw new Error( 'params.menu_id was not defined' );
+			}
+
+			/*
+			 * Since newly created sections won't be registered in PHP, we need to prevent the
+			 * preview's sending of the activeSections to result in this control
+			 * being deactivated when the preview refreshes. So we can hook onto
+			 * the setting that has the same ID and its presence can dictate
+			 * whether the section is active.
+			 */
+			section.active.validate = function() {
+				if ( ! api.has( section.id ) ) {
+					return false;
+				}
+				return !! api( section.id ).get();
+			};
+
+			section.populateControls();
+
+			section.navMenuLocationSettings = {};
+			section.assignedLocations = new api.Value( [] );
+
+			api.each(function( setting, id ) {
+				var matches = id.match( /^nav_menu_locations\[(.+?)]/ );
+				if ( matches ) {
+					section.navMenuLocationSettings[ matches[1] ] = setting;
+					setting.bind( function() {
+						section.refreshAssignedLocations();
+					});
+				}
+			});
+
+			section.assignedLocations.bind(function( to ) {
+				section.updateAssignedLocationsInSectionTitle( to );
+			});
+
+			section.refreshAssignedLocations();
+
+			api.bind( 'pane-contents-reflowed', function() {
+				// Skip menus that have been removed.
+				if ( ! section.contentContainer.parent().length ) {
+					return;
+				}
+				section.container.find( '.menu-item .menu-item-reorder-nav button' ).attr({ 'tabindex': '0', 'aria-hidden': 'false' });
+				section.container.find( '.menu-item.move-up-disabled .menus-move-up' ).attr({ 'tabindex': '-1', 'aria-hidden': 'true' });
+				section.container.find( '.menu-item.move-down-disabled .menus-move-down' ).attr({ 'tabindex': '-1', 'aria-hidden': 'true' });
+				section.container.find( '.menu-item.move-left-disabled .menus-move-left' ).attr({ 'tabindex': '-1', 'aria-hidden': 'true' });
+				section.container.find( '.menu-item.move-right-disabled .menus-move-right' ).attr({ 'tabindex': '-1', 'aria-hidden': 'true' });
+			} );
+
+			/**
+			 * Update the active field class for the content container for a given checkbox toggle.
+			 *
+			 * @this {jQuery}
+			 * @returns {void}
+			 */
+			handleFieldActiveToggle = function() {
+				var className = 'field-' + $( this ).val() + '-active';
+				section.contentContainer.toggleClass( className, $( this ).prop( 'checked' ) );
+			};
+			fieldActiveToggles = api.panel( 'nav_menus' ).contentContainer.find( '.metabox-prefs:first' ).find( '.hide-column-tog' );
+			fieldActiveToggles.each( handleFieldActiveToggle );
+			fieldActiveToggles.on( 'click', handleFieldActiveToggle );
+		},
+
+		populateControls: function() {
+			var section = this,
+				menuNameControlId,
+				menuLocationsControlId,
+				menuAutoAddControlId,
+				menuDeleteControlId,
+				menuControl,
+				menuNameControl,
+				menuLocationsControl,
+				menuAutoAddControl,
+				menuDeleteControl;
+
+			// Add the control for managing the menu name.
+			menuNameControlId = section.id + '[name]';
+			menuNameControl = api.control( menuNameControlId );
+			if ( ! menuNameControl ) {
+				menuNameControl = new api.controlConstructor.nav_menu_name( menuNameControlId, {
+					type: 'nav_menu_name',
+					label: api.Menus.data.l10n.menuNameLabel,
+					section: section.id,
+					priority: 0,
+					settings: {
+						'default': section.id
+					}
+				} );
+				api.control.add( menuNameControl );
+				menuNameControl.active.set( true );
+			}
+
+			// Add the menu control.
+			menuControl = api.control( section.id );
+			if ( ! menuControl ) {
+				menuControl = new api.controlConstructor.nav_menu( section.id, {
+					type: 'nav_menu',
+					section: section.id,
+					priority: 998,
+					settings: {
+						'default': section.id
+					},
+					menu_id: section.params.menu_id
+				} );
+				api.control.add( menuControl );
+				menuControl.active.set( true );
+			}
+
+			// Add the menu locations control.
+			menuLocationsControlId = section.id + '[locations]';
+			menuLocationsControl = api.control( menuLocationsControlId );
+			if ( ! menuLocationsControl ) {
+				menuLocationsControl = new api.controlConstructor.nav_menu_locations( menuLocationsControlId, {
+					section: section.id,
+					priority: 999,
+					settings: {
+						'default': section.id
+					},
+					menu_id: section.params.menu_id
+				} );
+				api.control.add( menuLocationsControl.id, menuLocationsControl );
+				menuControl.active.set( true );
+			}
+
+			// Add the control for managing the menu auto_add.
+			menuAutoAddControlId = section.id + '[auto_add]';
+			menuAutoAddControl = api.control( menuAutoAddControlId );
+			if ( ! menuAutoAddControl ) {
+				menuAutoAddControl = new api.controlConstructor.nav_menu_auto_add( menuAutoAddControlId, {
+					type: 'nav_menu_auto_add',
+					label: '',
+					section: section.id,
+					priority: 1000,
+					settings: {
+						'default': section.id
+					}
+				} );
+				api.control.add( menuAutoAddControl );
+				menuAutoAddControl.active.set( true );
+			}
+
+			// Add the control for deleting the menu
+			menuDeleteControlId = section.id + '[delete]';
+			menuDeleteControl = api.control( menuDeleteControlId );
+			if ( ! menuDeleteControl ) {
+				menuDeleteControl = new api.Control( menuDeleteControlId, {
+					section: section.id,
+					priority: 1001,
+					templateId: 'nav-menu-delete-button'
+				} );
+				api.control.add( menuDeleteControl.id, menuDeleteControl );
+				menuDeleteControl.active.set( true );
+				menuDeleteControl.deferred.embedded.done( function () {
+					menuDeleteControl.container.find( 'button' ).on( 'click', function() {
+						var menuId = section.params.menu_id;
+						var menuControl = api.Menus.getMenuControl( menuId );
+						menuControl.setting.set( false );
+					});
+				} );
+			}
+		},
+
+		/**
+		 *
+		 */
+		refreshAssignedLocations: function() {
+			var section = this,
+				menuTermId = section.params.menu_id,
+				currentAssignedLocations = [];
+			_.each( section.navMenuLocationSettings, function( setting, themeLocation ) {
+				if ( setting() === menuTermId ) {
+					currentAssignedLocations.push( themeLocation );
+				}
+			});
+			section.assignedLocations.set( currentAssignedLocations );
+		},
+
+		/**
+		 * @param {Array} themeLocationSlugs Theme location slugs.
+		 */
+		updateAssignedLocationsInSectionTitle: function( themeLocationSlugs ) {
+			var section = this,
+				$title;
+
+			$title = section.container.find( '.accordion-section-title:first' );
+			$title.find( '.menu-in-location' ).remove();
+			_.each( themeLocationSlugs, function( themeLocationSlug ) {
+				var $label, locationName;
+				$label = $( '<span class="menu-in-location"></span>' );
+				locationName = api.Menus.data.locationSlugMappedToName[ themeLocationSlug ];
+				$label.text( api.Menus.data.l10n.menuLocation.replace( '%s', locationName ) );
+				$title.append( $label );
+			});
+
+			section.container.toggleClass( 'assigned-to-menu-location', 0 !== themeLocationSlugs.length );
+
+		},
+
+		onChangeExpanded: function( expanded, args ) {
+			var section = this, completeCallback;
+
+			if ( expanded ) {
+				wpNavMenu.menuList = section.contentContainer;
+				wpNavMenu.targetList = wpNavMenu.menuList;
+
+				// Add attributes needed by wpNavMenu
+				$( '#menu-to-edit' ).removeAttr( 'id' );
+				wpNavMenu.menuList.attr( 'id', 'menu-to-edit' ).addClass( 'menu' );
+
+				_.each( api.section( section.id ).controls(), function( control ) {
+					if ( 'nav_menu_item' === control.params.type ) {
+						control.actuallyEmbed();
+					}
+				} );
+
+				// Make sure Sortables is initialized after the section has been expanded to prevent `offset` issues.
+				if ( args.completeCallback ) {
+					completeCallback = args.completeCallback;
+				}
+				args.completeCallback = function() {
+					if ( 'resolved' !== section.deferred.initSortables.state() ) {
+						wpNavMenu.initSortables(); // Depends on menu-to-edit ID being set above.
+						section.deferred.initSortables.resolve( wpNavMenu.menuList ); // Now MenuControl can extend the sortable.
+
+						// @todo Note that wp.customize.reflowPaneContents() is debounced, so this immediate change will show a slight flicker while priorities get updated.
+						api.control( 'nav_menu[' + String( section.params.menu_id ) + ']' ).reflowMenuItems();
+					}
+					if ( _.isFunction( completeCallback ) ) {
+						completeCallback();
+					}
+				};
+			}
+			api.Section.prototype.onChangeExpanded.call( section, expanded, args );
+		},
+
+		/**
+		 * Highlight how a user may create new menu items.
+		 *
+		 * This method reminds the user to create new menu items and how.
+		 * It's exposed this way because this class knows best which UI needs
+		 * highlighted but those expanding this section know more about why and
+		 * when the affordance should be highlighted.
+		 *
+		 * @since 4.9.0
+		 *
+		 * @returns {void}
+		 */
+		highlightNewItemButton: function() {
+			api.utils.highlightButton( this.contentContainer.find( '.add-new-menu-item' ), { delay: 2000 } );
+		}
+	});
+
+	/**
+	 * Create a nav menu setting and section.
+	 *
+	 * @since 4.9.0
+	 *
+	 * @param {string} [name=''] Nav menu name.
+	 * @returns {wp.customize.Menus.MenuSection} Added nav menu.
+	 */
+	api.Menus.createNavMenu = function createNavMenu( name ) {
+		var customizeId, placeholderId, setting;
+		placeholderId = api.Menus.generatePlaceholderAutoIncrementId();
+
+		customizeId = 'nav_menu[' + String( placeholderId ) + ']';
+
+		// Register the menu control setting.
+		setting = api.create( customizeId, customizeId, {}, {
+			type: 'nav_menu',
+			transport: api.Menus.data.settingTransport,
+			previewer: api.previewer
+		} );
+		setting.set( $.extend(
+			{},
+			api.Menus.data.defaultSettingValues.nav_menu,
+			{
+				name: name || ''
+			}
+		) );
+
+		/*
+		 * Add the menu section (and its controls).
+		 * Note that this will automatically create the required controls
+		 * inside via the Section's ready method.
+		 */
+		return api.section.add( new api.Menus.MenuSection( customizeId, {
+			panel: 'nav_menus',
+			title: displayNavMenuName( name ),
+			customizeAction: api.Menus.data.l10n.customizingMenus,
+			priority: 10,
+			menu_id: placeholderId
+		} ) );
+	};
+
+	/**
+	 * wp.customize.Menus.NewMenuSection
+	 *
+	 * Customizer section for new menus.
+	 *
+	 * @constructor
+	 * @augments wp.customize.Section
+	 */
+	api.Menus.NewMenuSection = api.Section.extend({
+
+		/**
+		 * Add behaviors for the accordion section.
+		 *
+		 * @since 4.3.0
+		 */
+		attachEvents: function() {
+			var section = this,
+				container = section.container,
+				contentContainer = section.contentContainer,
+				navMenuSettingPattern = /^nav_menu\[/;
+
+			section.headContainer.find( '.accordion-section-title' ).replaceWith(
+				wp.template( 'nav-menu-create-menu-section-title' )
+			);
+
+			/*
+			 * We have to manually handle section expanded because we do not
+			 * apply the `accordion-section-title` class to this button-driven section.
+			 */
+			container.on( 'click', '.customize-add-menu-button', function() {
+				section.expand();
+			});
+
+			contentContainer.on( 'keydown', '.menu-name-field', function( event ) {
+				if ( 13 === event.which ) { // Enter.
+					section.submit();
+				}
+			} );
+			contentContainer.on( 'click', '#customize-new-menu-submit', function( event ) {
+				section.submit();
+				event.stopPropagation();
+				event.preventDefault();
+			} );
+
+			/**
+			 * Get number of non-deleted nav menus.
+			 *
+			 * @since 4.9.0
+			 * @returns {number} Count.
+			 */
+			function getNavMenuCount() {
+				var count = 0;
+				api.each( function( setting ) {
+					if ( navMenuSettingPattern.test( setting.id ) && false !== setting.get() ) {
+						count += 1;
+					}
+				} );
+				return count;
+			}
+
+			/**
+			 * Update visibility of notice to prompt users to create menus.
+			 *
+			 * @since 4.9.0
+			 * @returns {void}
+			 */
+			function updateNoticeVisibility() {
+				container.find( '.add-new-menu-notice' ).prop( 'hidden', getNavMenuCount() > 0 );
+			}
+
+			/**
+			 * Handle setting addition.
+			 *
+			 * @since 4.9.0
+			 * @param {wp.customize.Setting} setting - Added setting.
+			 * @returns {void}
+			 */
+			function addChangeEventListener( setting ) {
+				if ( navMenuSettingPattern.test( setting.id ) ) {
+					setting.bind( updateNoticeVisibility );
+					updateNoticeVisibility();
+				}
+			}
+
+			/**
+			 * Handle setting removal.
+			 *
+			 * @since 4.9.0
+			 * @param {wp.customize.Setting} setting - Removed setting.
+			 * @returns {void}
+			 */
+			function removeChangeEventListener( setting ) {
+				if ( navMenuSettingPattern.test( setting.id ) ) {
+					setting.unbind( updateNoticeVisibility );
+					updateNoticeVisibility();
+				}
+			}
+
+			api.each( addChangeEventListener );
+			api.bind( 'add', addChangeEventListener );
+			api.bind( 'removed', removeChangeEventListener );
+			updateNoticeVisibility();
+
+			api.Section.prototype.attachEvents.apply( section, arguments );
+		},
+
+		/**
+		 * Set up the control.
+		 *
+		 * @since 4.9.0
+		 */
+		ready: function() {
+			this.populateControls();
+		},
+
+		/**
+		 * Create the controls for this section.
+		 *
+		 * @since 4.9.0
+		 */
+		populateControls: function() {
+			var section = this,
+				menuNameControlId,
+				menuLocationsControlId,
+				newMenuSubmitControlId,
+				menuNameControl,
+				menuLocationsControl,
+				newMenuSubmitControl;
+
+			menuNameControlId = section.id + '[name]';
+			menuNameControl = api.control( menuNameControlId );
+			if ( ! menuNameControl ) {
+				menuNameControl = new api.controlConstructor.nav_menu_name( menuNameControlId, {
+					label: api.Menus.data.l10n.menuNameLabel,
+					description: api.Menus.data.l10n.newMenuNameDescription,
+					section: section.id,
+					priority: 0
+				} );
+				api.control.add( menuNameControl.id, menuNameControl );
+				menuNameControl.active.set( true );
+			}
+
+			menuLocationsControlId = section.id + '[locations]';
+			menuLocationsControl = api.control( menuLocationsControlId );
+			if ( ! menuLocationsControl ) {
+				menuLocationsControl = new api.controlConstructor.nav_menu_locations( menuLocationsControlId, {
+					section: section.id,
+					priority: 1,
+					menu_id: '',
+					isCreating: true
+				} );
+				api.control.add( menuLocationsControlId, menuLocationsControl );
+				menuLocationsControl.active.set( true );
+			}
+
+			newMenuSubmitControlId = section.id + '[submit]';
+			newMenuSubmitControl = api.control( newMenuSubmitControlId );
+			if ( !newMenuSubmitControl ) {
+				newMenuSubmitControl = new api.Control( newMenuSubmitControlId, {
+					section: section.id,
+					priority: 1,
+					templateId: 'nav-menu-submit-new-button'
+				} );
+				api.control.add( newMenuSubmitControlId, newMenuSubmitControl );
+				newMenuSubmitControl.active.set( true );
+			}
+		},
+
+		/**
+		 * Create the new menu with name and location supplied by the user.
+		 *
+		 * @since 4.9.0
+		 */
+		submit: function() {
+			var section = this,
+				contentContainer = section.contentContainer,
+				nameInput = contentContainer.find( '.menu-name-field' ).first(),
+				name = nameInput.val(),
+				menuSection;
+
+			if ( ! name ) {
+				nameInput.addClass( 'invalid' );
+				nameInput.focus();
+				return;
+			}
+
+			menuSection = api.Menus.createNavMenu( name );
+
+			// Clear name field.
+			nameInput.val( '' );
+			nameInput.removeClass( 'invalid' );
+
+			contentContainer.find( '.assigned-menu-location input[type=checkbox]' ).each( function() {
+				var checkbox = $( this ),
+				navMenuLocationSetting;
+
+				if ( checkbox.prop( 'checked' ) ) {
+					navMenuLocationSetting = api( 'nav_menu_locations[' + checkbox.data( 'location-id' ) + ']' );
+					navMenuLocationSetting.set( menuSection.params.menu_id );
+
+					// Reset state for next new menu
+					checkbox.prop( 'checked', false );
+				}
+			} );
+
+			wp.a11y.speak( api.Menus.data.l10n.menuAdded );
+
+			// Focus on the new menu section.
+			menuSection.focus( {
+				completeCallback: function() {
+					menuSection.highlightNewItemButton();
+				}
+			} );
+		},
+
+		/**
+		 * Select a default location.
+		 *
+		 * This method selects a single location by default so we can support
+		 * creating a menu for a specific menu location.
+		 *
+		 * @since 4.9.0
+		 *
+		 * @param {string|null} locationId - The ID of the location to select. `null` clears all selections.
+		 * @returns {void}
+		 */
+		selectDefaultLocation: function( locationId ) {
+			var locationControl = api.control( this.id + '[locations]' ),
+				locationSelections = {};
+
+			if ( locationId !== null ) {
+				locationSelections[ locationId ] = true;
+			}
+
+			locationControl.setSelections( locationSelections );
+		}
+	});
+
+	/**
+	 * wp.customize.Menus.MenuLocationControl
+	 *
+	 * Customizer control for menu locations (rendered as a <select>).
+	 * Note that 'nav_menu_location' must match the WP_Customize_Nav_Menu_Location_Control::$type.
+	 *
+	 * @constructor
+	 * @augments wp.customize.Control
+	 */
+	api.Menus.MenuLocationControl = api.Control.extend({
+		initialize: function( id, options ) {
+			var control = this,
+				matches = id.match( /^nav_menu_locations\[(.+?)]/ );
+			control.themeLocation = matches[1];
+			api.Control.prototype.initialize.call( control, id, options );
+		},
+
+		ready: function() {
+			var control = this, navMenuIdRegex = /^nav_menu\[(-?\d+)]/;
+
+			// @todo It would be better if this was added directly on the setting itself, as opposed to the control.
+			control.setting.validate = function( value ) {
+				if ( '' === value ) {
+					return 0;
+				} else {
+					return parseInt( value, 10 );
+				}
+			};
+
+			// Create and Edit menu buttons.
+			control.container.find( '.create-menu' ).on( 'click', function() {
+				var addMenuSection = api.section( 'add_menu' );
+				addMenuSection.selectDefaultLocation( this.dataset.locationId );
+				addMenuSection.focus();
+			} );
+			control.container.find( '.edit-menu' ).on( 'click', function() {
+				var menuId = control.setting();
+				api.section( 'nav_menu[' + menuId + ']' ).focus();
+			});
+			control.setting.bind( 'change', function() {
+				var menuIsSelected = 0 !== control.setting();
+				control.container.find( '.create-menu' ).toggleClass( 'hidden', menuIsSelected );
+				control.container.find( '.edit-menu' ).toggleClass( 'hidden', ! menuIsSelected );
+			});
+
+			// Add/remove menus from the available options when they are added and removed.
+			api.bind( 'add', function( setting ) {
+				var option, menuId, matches = setting.id.match( navMenuIdRegex );
+				if ( ! matches || false === setting() ) {
+					return;
+				}
+				menuId = matches[1];
+				option = new Option( displayNavMenuName( setting().name ), menuId );
+				control.container.find( 'select' ).append( option );
+			});
+			api.bind( 'remove', function( setting ) {
+				var menuId, matches = setting.id.match( navMenuIdRegex );
+				if ( ! matches ) {
+					return;
+				}
+				menuId = parseInt( matches[1], 10 );
+				if ( control.setting() === menuId ) {
+					control.setting.set( '' );
+				}
+				control.container.find( 'option[value=' + menuId + ']' ).remove();
+			});
+			api.bind( 'change', function( setting ) {
+				var menuId, matches = setting.id.match( navMenuIdRegex );
+				if ( ! matches ) {
+					return;
+				}
+				menuId = parseInt( matches[1], 10 );
+				if ( false === setting() ) {
+					if ( control.setting() === menuId ) {
+						control.setting.set( '' );
+					}
+					control.container.find( 'option[value=' + menuId + ']' ).remove();
+				} else {
+					control.container.find( 'option[value=' + menuId + ']' ).text( displayNavMenuName( setting().name ) );
+				}
+			});
+		}
+	});
+
+	/**
+	 * wp.customize.Menus.MenuItemControl
+	 *
+	 * Customizer control for menu items.
+	 * Note that 'menu_item' must match the WP_Customize_Menu_Item_Control::$type.
+	 *
+	 * @constructor
+	 * @augments wp.customize.Control
+	 */
+	api.Menus.MenuItemControl = api.Control.extend({
+
+		/**
+		 * @inheritdoc
+		 */
+		initialize: function( id, options ) {
+			var control = this;
+			control.expanded = new api.Value( false );
+			control.expandedArgumentsQueue = [];
+			control.expanded.bind( function( expanded ) {
+				var args = control.expandedArgumentsQueue.shift();
+				args = $.extend( {}, control.defaultExpandedArguments, args );
+				control.onChangeExpanded( expanded, args );
+			});
+			api.Control.prototype.initialize.call( control, id, options );
+			control.active.validate = function() {
+				var value, section = api.section( control.section() );
+				if ( section ) {
+					value = section.active();
+				} else {
+					value = false;
+				}
+				return value;
+			};
+		},
+
+		/**
+		 * Override the embed() method to do nothing,
+		 * so that the control isn't embedded on load,
+		 * unless the containing section is already expanded.
+		 *
+		 * @since 4.3.0
+		 */
+		embed: function() {
+			var control = this,
+				sectionId = control.section(),
+				section;
+			if ( ! sectionId ) {
+				return;
+			}
+			section = api.section( sectionId );
+			if ( ( section && section.expanded() ) || api.settings.autofocus.control === control.id ) {
+				control.actuallyEmbed();
+			}
+		},
+
+		/**
+		 * This function is called in Section.onChangeExpanded() so the control
+		 * will only get embedded when the Section is first expanded.
+		 *
+		 * @since 4.3.0
+		 */
+		actuallyEmbed: function() {
+			var control = this;
+			if ( 'resolved' === control.deferred.embedded.state() ) {
+				return;
+			}
+			control.renderContent();
+			control.deferred.embedded.resolve(); // This triggers control.ready().
+		},
+
+		/**
+		 * Set up the control.
+		 */
+		ready: function() {
+			if ( 'undefined' === typeof this.params.menu_item_id ) {
+				throw new Error( 'params.menu_item_id was not defined' );
+			}
+
+			this._setupControlToggle();
+			this._setupReorderUI();
+			this._setupUpdateUI();
+			this._setupRemoveUI();
+			this._setupLinksUI();
+			this._setupTitleUI();
+		},
+
+		/**
+		 * Show/hide the settings when clicking on the menu item handle.
+		 */
+		_setupControlToggle: function() {
+			var control = this;
+
+			this.container.find( '.menu-item-handle' ).on( 'click', function( e ) {
+				e.preventDefault();
+				e.stopPropagation();
+				var menuControl = control.getMenuControl(),
+					isDeleteBtn = $( e.target ).is( '.item-delete, .item-delete *' ),
+					isAddNewBtn = $( e.target ).is( '.add-new-menu-item, .add-new-menu-item *' );
+
+				if ( $( 'body' ).hasClass( 'adding-menu-items' ) && ! isDeleteBtn && ! isAddNewBtn ) {
+					api.Menus.availableMenuItemsPanel.close();
+				}
+
+				if ( menuControl.isReordering || menuControl.isSorting ) {
+					return;
+				}
+				control.toggleForm();
+			} );
+		},
+
+		/**
+		 * Set up the menu-item-reorder-nav
+		 */
+		_setupReorderUI: function() {
+			var control = this, template, $reorderNav;
+
+			template = wp.template( 'menu-item-reorder-nav' );
+
+			// Add the menu item reordering elements to the menu item control.
+			control.container.find( '.item-controls' ).after( template );
+
+			// Handle clicks for up/down/left-right on the reorder nav.
+			$reorderNav = control.container.find( '.menu-item-reorder-nav' );
+			$reorderNav.find( '.menus-move-up, .menus-move-down, .menus-move-left, .menus-move-right' ).on( 'click', function() {
+				var moveBtn = $( this );
+				moveBtn.focus();
+
+				var isMoveUp = moveBtn.is( '.menus-move-up' ),
+					isMoveDown = moveBtn.is( '.menus-move-down' ),
+					isMoveLeft = moveBtn.is( '.menus-move-left' ),
+					isMoveRight = moveBtn.is( '.menus-move-right' );
+
+				if ( isMoveUp ) {
+					control.moveUp();
+				} else if ( isMoveDown ) {
+					control.moveDown();
+				} else if ( isMoveLeft ) {
+					control.moveLeft();
+				} else if ( isMoveRight ) {
+					control.moveRight();
+				}
+
+				moveBtn.focus(); // Re-focus after the container was moved.
+			} );
+		},
+
+		/**
+		 * Set up event handlers for menu item updating.
+		 */
+		_setupUpdateUI: function() {
+			var control = this,
+				settingValue = control.setting(),
+				updateNotifications;
+
+			control.elements = {};
+			control.elements.url = new api.Element( control.container.find( '.edit-menu-item-url' ) );
+			control.elements.title = new api.Element( control.container.find( '.edit-menu-item-title' ) );
+			control.elements.attr_title = new api.Element( control.container.find( '.edit-menu-item-attr-title' ) );
+			control.elements.target = new api.Element( control.container.find( '.edit-menu-item-target' ) );
+			control.elements.classes = new api.Element( control.container.find( '.edit-menu-item-classes' ) );
+			control.elements.xfn = new api.Element( control.container.find( '.edit-menu-item-xfn' ) );
+			control.elements.description = new api.Element( control.container.find( '.edit-menu-item-description' ) );
+			// @todo allow other elements, added by plugins, to be automatically picked up here; allow additional values to be added to setting array.
+
+			_.each( control.elements, function( element, property ) {
+				element.bind(function( value ) {
+					if ( element.element.is( 'input[type=checkbox]' ) ) {
+						value = ( value ) ? element.element.val() : '';
+					}
+
+					var settingValue = control.setting();
+					if ( settingValue && settingValue[ property ] !== value ) {
+						settingValue = _.clone( settingValue );
+						settingValue[ property ] = value;
+						control.setting.set( settingValue );
+					}
+				});
+				if ( settingValue ) {
+					if ( ( property === 'classes' || property === 'xfn' ) && _.isArray( settingValue[ property ] ) ) {
+						element.set( settingValue[ property ].join( ' ' ) );
+					} else {
+						element.set( settingValue[ property ] );
+					}
+				}
+			});
+
+			control.setting.bind(function( to, from ) {
+				var itemId = control.params.menu_item_id,
+					followingSiblingItemControls = [],
+					childrenItemControls = [],
+					menuControl;
+
+				if ( false === to ) {
+					menuControl = api.control( 'nav_menu[' + String( from.nav_menu_term_id ) + ']' );
+					control.container.remove();
+
+					_.each( menuControl.getMenuItemControls(), function( otherControl ) {
+						if ( from.menu_item_parent === otherControl.setting().menu_item_parent && otherControl.setting().position > from.position ) {
+							followingSiblingItemControls.push( otherControl );
+						} else if ( otherControl.setting().menu_item_parent === itemId ) {
+							childrenItemControls.push( otherControl );
+						}
+					});
+
+					// Shift all following siblings by the number of children this item has.
+					_.each( followingSiblingItemControls, function( followingSiblingItemControl ) {
+						var value = _.clone( followingSiblingItemControl.setting() );
+						value.position += childrenItemControls.length;
+						followingSiblingItemControl.setting.set( value );
+					});
+
+					// Now move the children up to be the new subsequent siblings.
+					_.each( childrenItemControls, function( childrenItemControl, i ) {
+						var value = _.clone( childrenItemControl.setting() );
+						value.position = from.position + i;
+						value.menu_item_parent = from.menu_item_parent;
+						childrenItemControl.setting.set( value );
+					});
+
+					menuControl.debouncedReflowMenuItems();
+				} else {
+					// Update the elements' values to match the new setting properties.
+					_.each( to, function( value, key ) {
+						if ( control.elements[ key] ) {
+							control.elements[ key ].set( to[ key ] );
+						}
+					} );
+					control.container.find( '.menu-item-data-parent-id' ).val( to.menu_item_parent );
+
+					// Handle UI updates when the position or depth (parent) change.
+					if ( to.position !== from.position || to.menu_item_parent !== from.menu_item_parent ) {
+						control.getMenuControl().debouncedReflowMenuItems();
+					}
+				}
+			});
+
+			// Style the URL field as invalid when there is an invalid_url notification.
+			updateNotifications = function() {
+				control.elements.url.element.toggleClass( 'invalid', control.setting.notifications.has( 'invalid_url' ) );
+			};
+			control.setting.notifications.bind( 'add', updateNotifications );
+			control.setting.notifications.bind( 'removed', updateNotifications );
+		},
+
+		/**
+		 * Set up event handlers for menu item deletion.
+		 */
+		_setupRemoveUI: function() {
+			var control = this, $removeBtn;
+
+			// Configure delete button.
+			$removeBtn = control.container.find( '.item-delete' );
+
+			$removeBtn.on( 'click', function() {
+				// Find an adjacent element to add focus to when this menu item goes away
+				var addingItems = true, $adjacentFocusTarget, $next, $prev;
+
+				if ( ! $( 'body' ).hasClass( 'adding-menu-items' ) ) {
+					addingItems = false;
+				}
+
+				$next = control.container.nextAll( '.customize-control-nav_menu_item:visible' ).first();
+				$prev = control.container.prevAll( '.customize-control-nav_menu_item:visible' ).first();
+
+				if ( $next.length ) {
+					$adjacentFocusTarget = $next.find( false === addingItems ? '.item-edit' : '.item-delete' ).first();
+				} else if ( $prev.length ) {
+					$adjacentFocusTarget = $prev.find( false === addingItems ? '.item-edit' : '.item-delete' ).first();
+				} else {
+					$adjacentFocusTarget = control.container.nextAll( '.customize-control-nav_menu' ).find( '.add-new-menu-item' ).first();
+				}
+
+				control.container.slideUp( function() {
+					control.setting.set( false );
+					wp.a11y.speak( api.Menus.data.l10n.itemDeleted );
+					$adjacentFocusTarget.focus(); // keyboard accessibility
+				} );
+
+				control.setting.set( false );
+			} );
+		},
+
+		_setupLinksUI: function() {
+			var $origBtn;
+
+			// Configure original link.
+			$origBtn = this.container.find( 'a.original-link' );
+
+			$origBtn.on( 'click', function( e ) {
+				e.preventDefault();
+				api.previewer.previewUrl( e.target.toString() );
+			} );
+		},
+
+		/**
+		 * Update item handle title when changed.
+		 */
+		_setupTitleUI: function() {
+			var control = this, titleEl;
+
+			// Ensure that whitespace is trimmed on blur so placeholder can be shown.
+			control.container.find( '.edit-menu-item-title' ).on( 'blur', function() {
+				$( this ).val( $.trim( $( this ).val() ) );
+			} );
+
+			titleEl = control.container.find( '.menu-item-title' );
+			control.setting.bind( function( item ) {
+				var trimmedTitle, titleText;
+				if ( ! item ) {
+					return;
+				}
+				trimmedTitle = $.trim( item.title );
+
+				titleText = trimmedTitle || item.original_title || api.Menus.data.l10n.untitled;
+
+				if ( item._invalid ) {
+					titleText = api.Menus.data.l10n.invalidTitleTpl.replace( '%s', titleText );
+				}
+
+				// Don't update to an empty title.
+				if ( trimmedTitle || item.original_title ) {
+					titleEl
+						.text( titleText )
+						.removeClass( 'no-title' );
+				} else {
+					titleEl
+						.text( titleText )
+						.addClass( 'no-title' );
+				}
+			} );
+		},
+
+		/**
+		 *
+		 * @returns {number}
+		 */
+		getDepth: function() {
+			var control = this, setting = control.setting(), depth = 0;
+			if ( ! setting ) {
+				return 0;
+			}
+			while ( setting && setting.menu_item_parent ) {
+				depth += 1;
+				control = api.control( 'nav_menu_item[' + setting.menu_item_parent + ']' );
+				if ( ! control ) {
+					break;
+				}
+				setting = control.setting();
+			}
+			return depth;
+		},
+
+		/**
+		 * Amend the control's params with the data necessary for the JS template just in time.
+		 */
+		renderContent: function() {
+			var control = this,
+				settingValue = control.setting(),
+				containerClasses;
+
+			control.params.title = settingValue.title || '';
+			control.params.depth = control.getDepth();
+			control.container.data( 'item-depth', control.params.depth );
+			containerClasses = [
+				'menu-item',
+				'menu-item-depth-' + String( control.params.depth ),
+				'menu-item-' + settingValue.object,
+				'menu-item-edit-inactive'
+			];
+
+			if ( settingValue._invalid ) {
+				containerClasses.push( 'menu-item-invalid' );
+				control.params.title = api.Menus.data.l10n.invalidTitleTpl.replace( '%s', control.params.title );
+			} else if ( 'draft' === settingValue.status ) {
+				containerClasses.push( 'pending' );
+				control.params.title = api.Menus.data.pendingTitleTpl.replace( '%s', control.params.title );
+			}
+
+			control.params.el_classes = containerClasses.join( ' ' );
+			control.params.item_type_label = settingValue.type_label;
+			control.params.item_type = settingValue.type;
+			control.params.url = settingValue.url;
+			control.params.target = settingValue.target;
+			control.params.attr_title = settingValue.attr_title;
+			control.params.classes = _.isArray( settingValue.classes ) ? settingValue.classes.join( ' ' ) : settingValue.classes;
+			control.params.attr_title = settingValue.attr_title;
+			control.params.xfn = settingValue.xfn;
+			control.params.description = settingValue.description;
+			control.params.parent = settingValue.menu_item_parent;
+			control.params.original_title = settingValue.original_title || '';
+
+			control.container.addClass( control.params.el_classes );
+
+			api.Control.prototype.renderContent.call( control );
+		},
+
+		/***********************************************************************
+		 * Begin public API methods
+		 **********************************************************************/
+
+		/**
+		 * @return {wp.customize.controlConstructor.nav_menu|null}
+		 */
+		getMenuControl: function() {
+			var control = this, settingValue = control.setting();
+			if ( settingValue && settingValue.nav_menu_term_id ) {
+				return api.control( 'nav_menu[' + settingValue.nav_menu_term_id + ']' );
+			} else {
+				return null;
+			}
+		},
+
+		/**
+		 * Expand the accordion section containing a control
+		 */
+		expandControlSection: function() {
+			var $section = this.container.closest( '.accordion-section' );
+			if ( ! $section.hasClass( 'open' ) ) {
+				$section.find( '.accordion-section-title:first' ).trigger( 'click' );
+			}
+		},
+
+		/**
+		 * @since 4.6.0
+		 *
+		 * @param {Boolean} expanded
+		 * @param {Object} [params]
+		 * @returns {Boolean} false if state already applied
+		 */
+		_toggleExpanded: api.Section.prototype._toggleExpanded,
+
+		/**
+		 * @since 4.6.0
+		 *
+		 * @param {Object} [params]
+		 * @returns {Boolean} false if already expanded
+		 */
+		expand: api.Section.prototype.expand,
+
+		/**
+		 * Expand the menu item form control.
+		 *
+		 * @since 4.5.0 Added params.completeCallback.
+		 *
+		 * @param {Object}   [params] - Optional params.
+		 * @param {Function} [params.completeCallback] - Function to call when the form toggle has finished animating.
+		 */
+		expandForm: function( params ) {
+			this.expand( params );
+		},
+
+		/**
+		 * @since 4.6.0
+		 *
+		 * @param {Object} [params]
+		 * @returns {Boolean} false if already collapsed
+		 */
+		collapse: api.Section.prototype.collapse,
+
+		/**
+		 * Collapse the menu item form control.
+		 *
+		 * @since 4.5.0 Added params.completeCallback.
+		 *
+		 * @param {Object}   [params] - Optional params.
+		 * @param {Function} [params.completeCallback] - Function to call when the form toggle has finished animating.
+		 */
+		collapseForm: function( params ) {
+			this.collapse( params );
+		},
+
+		/**
+		 * Expand or collapse the menu item control.
+		 *
+		 * @deprecated this is poor naming, and it is better to directly set control.expanded( showOrHide )
+		 * @since 4.5.0 Added params.completeCallback.
+		 *
+		 * @param {boolean}  [showOrHide] - If not supplied, will be inverse of current visibility
+		 * @param {Object}   [params] - Optional params.
+		 * @param {Function} [params.completeCallback] - Function to call when the form toggle has finished animating.
+		 */
+		toggleForm: function( showOrHide, params ) {
+			if ( typeof showOrHide === 'undefined' ) {
+				showOrHide = ! this.expanded();
+			}
+			if ( showOrHide ) {
+				this.expand( params );
+			} else {
+				this.collapse( params );
+			}
+		},
+
+		/**
+		 * Expand or collapse the menu item control.
+		 *
+		 * @since 4.6.0
+		 * @param {boolean}  [showOrHide] - If not supplied, will be inverse of current visibility
+		 * @param {Object}   [params] - Optional params.
+		 * @param {Function} [params.completeCallback] - Function to call when the form toggle has finished animating.
+		 */
+		onChangeExpanded: function( showOrHide, params ) {
+			var self = this, $menuitem, $inside, complete;
+
+			$menuitem = this.container;
+			$inside = $menuitem.find( '.menu-item-settings:first' );
+			if ( 'undefined' === typeof showOrHide ) {
+				showOrHide = ! $inside.is( ':visible' );
+			}
+
+			// Already expanded or collapsed.
+			if ( $inside.is( ':visible' ) === showOrHide ) {
+				if ( params && params.completeCallback ) {
+					params.completeCallback();
+				}
+				return;
+			}
+
+			if ( showOrHide ) {
+				// Close all other menu item controls before expanding this one.
+				api.control.each( function( otherControl ) {
+					if ( self.params.type === otherControl.params.type && self !== otherControl ) {
+						otherControl.collapseForm();
+					}
+				} );
+
+				complete = function() {
+					$menuitem
+						.removeClass( 'menu-item-edit-inactive' )
+						.addClass( 'menu-item-edit-active' );
+					self.container.trigger( 'expanded' );
+
+					if ( params && params.completeCallback ) {
+						params.completeCallback();
+					}
+				};
+
+				$menuitem.find( '.item-edit' ).attr( 'aria-expanded', 'true' );
+				$inside.slideDown( 'fast', complete );
+
+				self.container.trigger( 'expand' );
+			} else {
+				complete = function() {
+					$menuitem
+						.addClass( 'menu-item-edit-inactive' )
+						.removeClass( 'menu-item-edit-active' );
+					self.container.trigger( 'collapsed' );
+
+					if ( params && params.completeCallback ) {
+						params.completeCallback();
+					}
+				};
+
+				self.container.trigger( 'collapse' );
+
+				$menuitem.find( '.item-edit' ).attr( 'aria-expanded', 'false' );
+				$inside.slideUp( 'fast', complete );
+			}
+		},
+
+		/**
+		 * Expand the containing menu section, expand the form, and focus on
+		 * the first input in the control.
+		 *
+		 * @since 4.5.0 Added params.completeCallback.
+		 *
+		 * @param {Object}   [params] - Params object.
+		 * @param {Function} [params.completeCallback] - Optional callback function when focus has completed.
+		 */
+		focus: function( params ) {
+			params = params || {};
+			var control = this, originalCompleteCallback = params.completeCallback, focusControl;
+
+			focusControl = function() {
+				control.expandControlSection();
+
+				params.completeCallback = function() {
+					var focusable;
+
+					// Note that we can't use :focusable due to a jQuery UI issue. See: https://github.com/jquery/jquery-ui/pull/1583
+					focusable = control.container.find( '.menu-item-settings' ).find( 'input, select, textarea, button, object, a[href], [tabindex]' ).filter( ':visible' );
+					focusable.first().focus();
+
+					if ( originalCompleteCallback ) {
+						originalCompleteCallback();
+					}
+				};
+
+				control.expandForm( params );
+			};
+
+			if ( api.section.has( control.section() ) ) {
+				api.section( control.section() ).expand( {
+					completeCallback: focusControl
+				} );
+			} else {
+				focusControl();
+			}
+		},
+
+		/**
+		 * Move menu item up one in the menu.
+		 */
+		moveUp: function() {
+			this._changePosition( -1 );
+			wp.a11y.speak( api.Menus.data.l10n.movedUp );
+		},
+
+		/**
+		 * Move menu item up one in the menu.
+		 */
+		moveDown: function() {
+			this._changePosition( 1 );
+			wp.a11y.speak( api.Menus.data.l10n.movedDown );
+		},
+		/**
+		 * Move menu item and all children up one level of depth.
+		 */
+		moveLeft: function() {
+			this._changeDepth( -1 );
+			wp.a11y.speak( api.Menus.data.l10n.movedLeft );
+		},
+
+		/**
+		 * Move menu item and children one level deeper, as a submenu of the previous item.
+		 */
+		moveRight: function() {
+			this._changeDepth( 1 );
+			wp.a11y.speak( api.Menus.data.l10n.movedRight );
+		},
+
+		/**
+		 * Note that this will trigger a UI update, causing child items to
+		 * move as well and cardinal order class names to be updated.
+		 *
+		 * @private
+		 *
+		 * @param {Number} offset 1|-1
+		 */
+		_changePosition: function( offset ) {
+			var control = this,
+				adjacentSetting,
+				settingValue = _.clone( control.setting() ),
+				siblingSettings = [],
+				realPosition;
+
+			if ( 1 !== offset && -1 !== offset ) {
+				throw new Error( 'Offset changes by 1 are only supported.' );
+			}
+
+			// Skip moving deleted items.
+			if ( ! control.setting() ) {
+				return;
+			}
+
+			// Locate the other items under the same parent (siblings).
+			_( control.getMenuControl().getMenuItemControls() ).each(function( otherControl ) {
+				if ( otherControl.setting().menu_item_parent === settingValue.menu_item_parent ) {
+					siblingSettings.push( otherControl.setting );
+				}
+			});
+			siblingSettings.sort(function( a, b ) {
+				return a().position - b().position;
+			});
+
+			realPosition = _.indexOf( siblingSettings, control.setting );
+			if ( -1 === realPosition ) {
+				throw new Error( 'Expected setting to be among siblings.' );
+			}
+
+			// Skip doing anything if the item is already at the edge in the desired direction.
+			if ( ( realPosition === 0 && offset < 0 ) || ( realPosition === siblingSettings.length - 1 && offset > 0 ) ) {
+				// @todo Should we allow a menu item to be moved up to break it out of a parent? Adopt with previous or following parent?
+				return;
+			}
+
+			// Update any adjacent menu item setting to take on this item's position.
+			adjacentSetting = siblingSettings[ realPosition + offset ];
+			if ( adjacentSetting ) {
+				adjacentSetting.set( $.extend(
+					_.clone( adjacentSetting() ),
+					{
+						position: settingValue.position
+					}
+				) );
+			}
+
+			settingValue.position += offset;
+			control.setting.set( settingValue );
+		},
+
+		/**
+		 * Note that this will trigger a UI update, causing child items to
+		 * move as well and cardinal order class names to be updated.
+		 *
+		 * @private
+		 *
+		 * @param {Number} offset 1|-1
+		 */
+		_changeDepth: function( offset ) {
+			if ( 1 !== offset && -1 !== offset ) {
+				throw new Error( 'Offset changes by 1 are only supported.' );
+			}
+			var control = this,
+				settingValue = _.clone( control.setting() ),
+				siblingControls = [],
+				realPosition,
+				siblingControl,
+				parentControl;
+
+			// Locate the other items under the same parent (siblings).
+			_( control.getMenuControl().getMenuItemControls() ).each(function( otherControl ) {
+				if ( otherControl.setting().menu_item_parent === settingValue.menu_item_parent ) {
+					siblingControls.push( otherControl );
+				}
+			});
+			siblingControls.sort(function( a, b ) {
+				return a.setting().position - b.setting().position;
+			});
+
+			realPosition = _.indexOf( siblingControls, control );
+			if ( -1 === realPosition ) {
+				throw new Error( 'Expected control to be among siblings.' );
+			}
+
+			if ( -1 === offset ) {
+				// Skip moving left an item that is already at the top level.
+				if ( ! settingValue.menu_item_parent ) {
+					return;
+				}
+
+				parentControl = api.control( 'nav_menu_item[' + settingValue.menu_item_parent + ']' );
+
+				// Make this control the parent of all the following siblings.
+				_( siblingControls ).chain().slice( realPosition ).each(function( siblingControl, i ) {
+					siblingControl.setting.set(
+						$.extend(
+							{},
+							siblingControl.setting(),
+							{
+								menu_item_parent: control.params.menu_item_id,
+								position: i
+							}
+						)
+					);
+				});
+
+				// Increase the positions of the parent item's subsequent children to make room for this one.
+				_( control.getMenuControl().getMenuItemControls() ).each(function( otherControl ) {
+					var otherControlSettingValue, isControlToBeShifted;
+					isControlToBeShifted = (
+						otherControl.setting().menu_item_parent === parentControl.setting().menu_item_parent &&
+						otherControl.setting().position > parentControl.setting().position
+					);
+					if ( isControlToBeShifted ) {
+						otherControlSettingValue = _.clone( otherControl.setting() );
+						otherControl.setting.set(
+							$.extend(
+								otherControlSettingValue,
+								{ position: otherControlSettingValue.position + 1 }
+							)
+						);
+					}
+				});
+
+				// Make this control the following sibling of its parent item.
+				settingValue.position = parentControl.setting().position + 1;
+				settingValue.menu_item_parent = parentControl.setting().menu_item_parent;
+				control.setting.set( settingValue );
+
+			} else if ( 1 === offset ) {
+				// Skip moving right an item that doesn't have a previous sibling.
+				if ( realPosition === 0 ) {
+					return;
+				}
+
+				// Make the control the last child of the previous sibling.
+				siblingControl = siblingControls[ realPosition - 1 ];
+				settingValue.menu_item_parent = siblingControl.params.menu_item_id;
+				settingValue.position = 0;
+				_( control.getMenuControl().getMenuItemControls() ).each(function( otherControl ) {
+					if ( otherControl.setting().menu_item_parent === settingValue.menu_item_parent ) {
+						settingValue.position = Math.max( settingValue.position, otherControl.setting().position );
+					}
+				});
+				settingValue.position += 1;
+				control.setting.set( settingValue );
+			}
+		}
+	} );
+
+	/**
+	 * wp.customize.Menus.MenuNameControl
+	 *
+	 * Customizer control for a nav menu's name.
+	 *
+	 * @constructor
+	 * @augments wp.customize.Control
+	 */
+	api.Menus.MenuNameControl = api.Control.extend({
+
+		ready: function() {
+			var control = this;
+
+			if ( control.setting ) {
+				var settingValue = control.setting();
+
+				control.nameElement = new api.Element( control.container.find( '.menu-name-field' ) );
+
+				control.nameElement.bind(function( value ) {
+					var settingValue = control.setting();
+					if ( settingValue && settingValue.name !== value ) {
+						settingValue = _.clone( settingValue );
+						settingValue.name = value;
+						control.setting.set( settingValue );
+					}
+				});
+				if ( settingValue ) {
+					control.nameElement.set( settingValue.name );
+				}
+
+				control.setting.bind(function( object ) {
+					if ( object ) {
+						control.nameElement.set( object.name );
+					}
+				});
+			}
+		}
+	});
+
+	/**
+	 * wp.customize.Menus.MenuLocationsControl
+	 *
+	 * Customizer control for a nav menu's locations.
+	 *
+	 * @since 4.9.0
+	 * @constructor
+	 * @augments wp.customize.Control
+	 */
+	api.Menus.MenuLocationsControl = api.Control.extend({
+
+		/**
+		 * Set up the control.
+		 *
+		 * @since 4.9.0
+		 */
+		ready: function () {
+			var control = this;
+
+			control.container.find( '.assigned-menu-location' ).each(function() {
+				var container = $( this ),
+					checkbox = container.find( 'input[type=checkbox]' ),
+					element = new api.Element( checkbox ),
+					navMenuLocationSetting = api( 'nav_menu_locations[' + checkbox.data( 'location-id' ) + ']' ),
+					isNewMenu = control.params.menu_id === '',
+					updateCheckbox = isNewMenu ? _.noop : function( checked ) {
+						element.set( checked );
+					},
+					updateSetting = isNewMenu ? _.noop : function( checked ) {
+						navMenuLocationSetting.set( checked ? control.params.menu_id : 0 );
+					},
+					updateSelectedMenuLabel = function( selectedMenuId ) {
+						var menuSetting = api( 'nav_menu[' + String( selectedMenuId ) + ']' );
+						if ( ! selectedMenuId || ! menuSetting || ! menuSetting() ) {
+							container.find( '.theme-location-set' ).hide();
+						} else {
+							container.find( '.theme-location-set' ).show().find( 'span' ).text( displayNavMenuName( menuSetting().name ) );
+						}
+					};
+
+				updateCheckbox( navMenuLocationSetting.get() === control.params.menu_id );
+
+				checkbox.on( 'change', function() {
+					// Note: We can't use element.bind( function( checked ){ ... } ) here because it will trigger a change as well.
+					updateSetting( this.checked );
+				} );
+
+				navMenuLocationSetting.bind( function( selectedMenuId ) {
+					updateCheckbox( selectedMenuId === control.params.menu_id );
+					updateSelectedMenuLabel( selectedMenuId );
+				} );
+				updateSelectedMenuLabel( navMenuLocationSetting.get() );
+			});
+		},
+
+		/**
+		 * Set the selected locations.
+		 *
+		 * This method sets the selected locations and allows us to do things like
+		 * set the default location for a new menu.
+		 *
+		 * @since 4.9.0
+		 *
+		 * @param {Object.<string,boolean>} selections - A map of location selections.
+		 * @returns {void}
+		 */
+		setSelections: function( selections ) {
+			this.container.find( '.menu-location' ).each( function( i, checkboxNode ) {
+				var locationId = checkboxNode.dataset.locationId;
+				checkboxNode.checked = locationId in selections ? selections[ locationId ] : false;
+			} );
+		}
+	});
+
+	/**
+	 * wp.customize.Menus.MenuAutoAddControl
+	 *
+	 * Customizer control for a nav menu's auto add.
+	 *
+	 * @constructor
+	 * @augments wp.customize.Control
+	 */
+	api.Menus.MenuAutoAddControl = api.Control.extend({
+
+		ready: function() {
+			var control = this,
+				settingValue = control.setting();
+
+			/*
+			 * Since the control is not registered in PHP, we need to prevent the
+			 * preview's sending of the activeControls to result in this control
+			 * being deactivated.
+			 */
+			control.active.validate = function() {
+				var value, section = api.section( control.section() );
+				if ( section ) {
+					value = section.active();
+				} else {
+					value = false;
+				}
+				return value;
+			};
+
+			control.autoAddElement = new api.Element( control.container.find( 'input[type=checkbox].auto_add' ) );
+
+			control.autoAddElement.bind(function( value ) {
+				var settingValue = control.setting();
+				if ( settingValue && settingValue.name !== value ) {
+					settingValue = _.clone( settingValue );
+					settingValue.auto_add = value;
+					control.setting.set( settingValue );
+				}
+			});
+			if ( settingValue ) {
+				control.autoAddElement.set( settingValue.auto_add );
+			}
+
+			control.setting.bind(function( object ) {
+				if ( object ) {
+					control.autoAddElement.set( object.auto_add );
+				}
+			});
+		}
+
+	});
+
+	/**
+	 * wp.customize.Menus.MenuControl
+	 *
+	 * Customizer control for menus.
+	 * Note that 'nav_menu' must match the WP_Menu_Customize_Control::$type
+	 *
+	 * @constructor
+	 * @augments wp.customize.Control
+	 */
+	api.Menus.MenuControl = api.Control.extend({
+		/**
+		 * Set up the control.
+		 */
+		ready: function() {
+			var control = this,
+				section = api.section( control.section() ),
+				menuId = control.params.menu_id,
+				menu = control.setting(),
+				name,
+				widgetTemplate,
+				select;
+
+			if ( 'undefined' === typeof this.params.menu_id ) {
+				throw new Error( 'params.menu_id was not defined' );
+			}
+
+			/*
+			 * Since the control is not registered in PHP, we need to prevent the
+			 * preview's sending of the activeControls to result in this control
+			 * being deactivated.
+			 */
+			control.active.validate = function() {
+				var value;
+				if ( section ) {
+					value = section.active();
+				} else {
+					value = false;
+				}
+				return value;
+			};
+
+			control.$controlSection = section.headContainer;
+			control.$sectionContent = control.container.closest( '.accordion-section-content' );
+
+			this._setupModel();
+
+			api.section( control.section(), function( section ) {
+				section.deferred.initSortables.done(function( menuList ) {
+					control._setupSortable( menuList );
+				});
+			} );
+
+			this._setupAddition();
+			this._setupTitle();
+
+			// Add menu to Navigation Menu widgets.
+			if ( menu ) {
+				name = displayNavMenuName( menu.name );
+
+				// Add the menu to the existing controls.
+				api.control.each( function( widgetControl ) {
+					if ( ! widgetControl.extended( api.controlConstructor.widget_form ) || 'nav_menu' !== widgetControl.params.widget_id_base ) {
+						return;
+					}
+					widgetControl.container.find( '.nav-menu-widget-form-controls:first' ).show();
+					widgetControl.container.find( '.nav-menu-widget-no-menus-message:first' ).hide();
+
+					select = widgetControl.container.find( 'select' );
+					if ( 0 === select.find( 'option[value=' + String( menuId ) + ']' ).length ) {
+						select.append( new Option( name, menuId ) );
+					}
+				} );
+
+				// Add the menu to the widget template.
+				widgetTemplate = $( '#available-widgets-list .widget-tpl:has( input.id_base[ value=nav_menu ] )' );
+				widgetTemplate.find( '.nav-menu-widget-form-controls:first' ).show();
+				widgetTemplate.find( '.nav-menu-widget-no-menus-message:first' ).hide();
+				select = widgetTemplate.find( '.widget-inside select:first' );
+				if ( 0 === select.find( 'option[value=' + String( menuId ) + ']' ).length ) {
+					select.append( new Option( name, menuId ) );
+				}
+			}
+
+			/*
+			 * Wait for menu items to be added.
+			 * Ideally, we'd bind to an event indicating construction is complete,
+			 * but deferring appears to be the best option today.
+			 */
+			_.defer( function () {
+				control.updateInvitationVisibility();
+			} );
+		},
+
+		/**
+		 * Update ordering of menu item controls when the setting is updated.
+		 */
+		_setupModel: function() {
+			var control = this,
+				menuId = control.params.menu_id;
+
+			control.setting.bind( function( to ) {
+				var name;
+				if ( false === to ) {
+					control._handleDeletion();
+				} else {
+					// Update names in the Navigation Menu widgets.
+					name = displayNavMenuName( to.name );
+					api.control.each( function( widgetControl ) {
+						if ( ! widgetControl.extended( api.controlConstructor.widget_form ) || 'nav_menu' !== widgetControl.params.widget_id_base ) {
+							return;
+						}
+						var select = widgetControl.container.find( 'select' );
+						select.find( 'option[value=' + String( menuId ) + ']' ).text( name );
+					});
+				}
+			} );
+		},
+
+		/**
+		 * Allow items in each menu to be re-ordered, and for the order to be previewed.
+		 *
+		 * Notice that the UI aspects here are handled by wpNavMenu.initSortables()
+		 * which is called in MenuSection.onChangeExpanded()
+		 *
+		 * @param {object} menuList - The element that has sortable().
+		 */
+		_setupSortable: function( menuList ) {
+			var control = this;
+
+			if ( ! menuList.is( control.$sectionContent ) ) {
+				throw new Error( 'Unexpected menuList.' );
+			}
+
+			menuList.on( 'sortstart', function() {
+				control.isSorting = true;
+			});
+
+			menuList.on( 'sortstop', function() {
+				setTimeout( function() { // Next tick.
+					var menuItemContainerIds = control.$sectionContent.sortable( 'toArray' ),
+						menuItemControls = [],
+						position = 0,
+						priority = 10;
+
+					control.isSorting = false;
+
+					// Reset horizontal scroll position when done dragging.
+					control.$sectionContent.scrollLeft( 0 );
+
+					_.each( menuItemContainerIds, function( menuItemContainerId ) {
+						var menuItemId, menuItemControl, matches;
+						matches = menuItemContainerId.match( /^customize-control-nav_menu_item-(-?\d+)$/, '' );
+						if ( ! matches ) {
+							return;
+						}
+						menuItemId = parseInt( matches[1], 10 );
+						menuItemControl = api.control( 'nav_menu_item[' + String( menuItemId ) + ']' );
+						if ( menuItemControl ) {
+							menuItemControls.push( menuItemControl );
+						}
+					} );
+
+					_.each( menuItemControls, function( menuItemControl ) {
+						if ( false === menuItemControl.setting() ) {
+							// Skip deleted items.
+							return;
+						}
+						var setting = _.clone( menuItemControl.setting() );
+						position += 1;
+						priority += 1;
+						setting.position = position;
+						menuItemControl.priority( priority );
+
+						// Note that wpNavMenu will be setting this .menu-item-data-parent-id input's value.
+						setting.menu_item_parent = parseInt( menuItemControl.container.find( '.menu-item-data-parent-id' ).val(), 10 );
+						if ( ! setting.menu_item_parent ) {
+							setting.menu_item_parent = 0;
+						}
+
+						menuItemControl.setting.set( setting );
+					});
+				});
+
+			});
+			control.isReordering = false;
+
+			/**
+			 * Keyboard-accessible reordering.
+			 */
+			this.container.find( '.reorder-toggle' ).on( 'click', function() {
+				control.toggleReordering( ! control.isReordering );
+			} );
+		},
+
+		/**
+		 * Set up UI for adding a new menu item.
+		 */
+		_setupAddition: function() {
+			var self = this;
+
+			this.container.find( '.add-new-menu-item' ).on( 'click', function( event ) {
+				if ( self.$sectionContent.hasClass( 'reordering' ) ) {
+					return;
+				}
+
+				if ( ! $( 'body' ).hasClass( 'adding-menu-items' ) ) {
+					$( this ).attr( 'aria-expanded', 'true' );
+					api.Menus.availableMenuItemsPanel.open( self );
+				} else {
+					$( this ).attr( 'aria-expanded', 'false' );
+					api.Menus.availableMenuItemsPanel.close();
+					event.stopPropagation();
+				}
+			} );
+		},
+
+		_handleDeletion: function() {
+			var control = this,
+				section,
+				menuId = control.params.menu_id,
+				removeSection,
+				widgetTemplate,
+				navMenuCount = 0;
+			section = api.section( control.section() );
+			removeSection = function() {
+				section.container.remove();
+				api.section.remove( section.id );
+			};
+
+			if ( section && section.expanded() ) {
+				section.collapse({
+					completeCallback: function() {
+						removeSection();
+						wp.a11y.speak( api.Menus.data.l10n.menuDeleted );
+						api.panel( 'nav_menus' ).focus();
+					}
+				});
+			} else {
+				removeSection();
+			}
+
+			api.each(function( setting ) {
+				if ( /^nav_menu\[/.test( setting.id ) && false !== setting() ) {
+					navMenuCount += 1;
+				}
+			});
+
+			// Remove the menu from any Navigation Menu widgets.
+			api.control.each(function( widgetControl ) {
+				if ( ! widgetControl.extended( api.controlConstructor.widget_form ) || 'nav_menu' !== widgetControl.params.widget_id_base ) {
+					return;
+				}
+				var select = widgetControl.container.find( 'select' );
+				if ( select.val() === String( menuId ) ) {
+					select.prop( 'selectedIndex', 0 ).trigger( 'change' );
+				}
+
+				widgetControl.container.find( '.nav-menu-widget-form-controls:first' ).toggle( 0 !== navMenuCount );
+				widgetControl.container.find( '.nav-menu-widget-no-menus-message:first' ).toggle( 0 === navMenuCount );
+				widgetControl.container.find( 'option[value=' + String( menuId ) + ']' ).remove();
+			});
+
+			// Remove the menu to the nav menu widget template.
+			widgetTemplate = $( '#available-widgets-list .widget-tpl:has( input.id_base[ value=nav_menu ] )' );
+			widgetTemplate.find( '.nav-menu-widget-form-controls:first' ).toggle( 0 !== navMenuCount );
+			widgetTemplate.find( '.nav-menu-widget-no-menus-message:first' ).toggle( 0 === navMenuCount );
+			widgetTemplate.find( 'option[value=' + String( menuId ) + ']' ).remove();
+		},
+
+		/**
+		 * Update Section Title as menu name is changed.
+		 */
+		_setupTitle: function() {
+			var control = this;
+
+			control.setting.bind( function( menu ) {
+				if ( ! menu ) {
+					return;
+				}
+
+				var section = api.section( control.section() ),
+					menuId = control.params.menu_id,
+					controlTitle = section.headContainer.find( '.accordion-section-title' ),
+					sectionTitle = section.contentContainer.find( '.customize-section-title h3' ),
+					location = section.headContainer.find( '.menu-in-location' ),
+					action = sectionTitle.find( '.customize-action' ),
+					name = displayNavMenuName( menu.name );
+
+				// Update the control title
+				controlTitle.text( name );
+				if ( location.length ) {
+					location.appendTo( controlTitle );
+				}
+
+				// Update the section title
+				sectionTitle.text( name );
+				if ( action.length ) {
+					action.prependTo( sectionTitle );
+				}
+
+				// Update the nav menu name in location selects.
+				api.control.each( function( control ) {
+					if ( /^nav_menu_locations\[/.test( control.id ) ) {
+						control.container.find( 'option[value=' + menuId + ']' ).text( name );
+					}
+				} );
+
+				// Update the nav menu name in all location checkboxes.
+				section.contentContainer.find( '.customize-control-checkbox input' ).each( function() {
+					if ( $( this ).prop( 'checked' ) ) {
+						$( '.current-menu-location-name-' + $( this ).data( 'location-id' ) ).text( name );
+					}
+				} );
+			} );
+		},
+
+		/***********************************************************************
+		 * Begin public API methods
+		 **********************************************************************/
+
+		/**
+		 * Enable/disable the reordering UI
+		 *
+		 * @param {Boolean} showOrHide to enable/disable reordering
+		 */
+		toggleReordering: function( showOrHide ) {
+			var addNewItemBtn = this.container.find( '.add-new-menu-item' ),
+				reorderBtn = this.container.find( '.reorder-toggle' ),
+				itemsTitle = this.$sectionContent.find( '.item-title' );
+
+			showOrHide = Boolean( showOrHide );
+
+			if ( showOrHide === this.$sectionContent.hasClass( 'reordering' ) ) {
+				return;
+			}
+
+			this.isReordering = showOrHide;
+			this.$sectionContent.toggleClass( 'reordering', showOrHide );
+			this.$sectionContent.sortable( this.isReordering ? 'disable' : 'enable' );
+			if ( this.isReordering ) {
+				addNewItemBtn.attr({ 'tabindex': '-1', 'aria-hidden': 'true' });
+				reorderBtn.attr( 'aria-label', api.Menus.data.l10n.reorderLabelOff );
+				wp.a11y.speak( api.Menus.data.l10n.reorderModeOn );
+				itemsTitle.attr( 'aria-hidden', 'false' );
+			} else {
+				addNewItemBtn.removeAttr( 'tabindex aria-hidden' );
+				reorderBtn.attr( 'aria-label', api.Menus.data.l10n.reorderLabelOn );
+				wp.a11y.speak( api.Menus.data.l10n.reorderModeOff );
+				itemsTitle.attr( 'aria-hidden', 'true' );
+			}
+
+			if ( showOrHide ) {
+				_( this.getMenuItemControls() ).each( function( formControl ) {
+					formControl.collapseForm();
+				} );
+			}
+		},
+
+		/**
+		 * @return {wp.customize.controlConstructor.nav_menu_item[]}
+		 */
+		getMenuItemControls: function() {
+			var menuControl = this,
+				menuItemControls = [],
+				menuTermId = menuControl.params.menu_id;
+
+			api.control.each(function( control ) {
+				if ( 'nav_menu_item' === control.params.type && control.setting() && menuTermId === control.setting().nav_menu_term_id ) {
+					menuItemControls.push( control );
+				}
+			});
+
+			return menuItemControls;
+		},
+
+		/**
+		 * Make sure that each menu item control has the proper depth.
+		 */
+		reflowMenuItems: function() {
+			var menuControl = this,
+				menuItemControls = menuControl.getMenuItemControls(),
+				reflowRecursively;
+
+			reflowRecursively = function( context ) {
+				var currentMenuItemControls = [],
+					thisParent = context.currentParent;
+				_.each( context.menuItemControls, function( menuItemControl ) {
+					if ( thisParent === menuItemControl.setting().menu_item_parent ) {
+						currentMenuItemControls.push( menuItemControl );
+						// @todo We could remove this item from menuItemControls now, for efficiency.
+					}
+				});
+				currentMenuItemControls.sort( function( a, b ) {
+					return a.setting().position - b.setting().position;
+				});
+
+				_.each( currentMenuItemControls, function( menuItemControl ) {
+					// Update position.
+					context.currentAbsolutePosition += 1;
+					menuItemControl.priority.set( context.currentAbsolutePosition ); // This will change the sort order.
+
+					// Update depth.
+					if ( ! menuItemControl.container.hasClass( 'menu-item-depth-' + String( context.currentDepth ) ) ) {
+						_.each( menuItemControl.container.prop( 'className' ).match( /menu-item-depth-\d+/g ), function( className ) {
+							menuItemControl.container.removeClass( className );
+						});
+						menuItemControl.container.addClass( 'menu-item-depth-' + String( context.currentDepth ) );
+					}
+					menuItemControl.container.data( 'item-depth', context.currentDepth );
+
+					// Process any children items.
+					context.currentDepth += 1;
+					context.currentParent = menuItemControl.params.menu_item_id;
+					reflowRecursively( context );
+					context.currentDepth -= 1;
+					context.currentParent = thisParent;
+				});
+
+				// Update class names for reordering controls.
+				if ( currentMenuItemControls.length ) {
+					_( currentMenuItemControls ).each(function( menuItemControl ) {
+						menuItemControl.container.removeClass( 'move-up-disabled move-down-disabled move-left-disabled move-right-disabled' );
+						if ( 0 === context.currentDepth ) {
+							menuItemControl.container.addClass( 'move-left-disabled' );
+						} else if ( 10 === context.currentDepth ) {
+							menuItemControl.container.addClass( 'move-right-disabled' );
+						}
+					});
+
+					currentMenuItemControls[0].container
+						.addClass( 'move-up-disabled' )
+						.addClass( 'move-right-disabled' )
+						.toggleClass( 'move-down-disabled', 1 === currentMenuItemControls.length );
+					currentMenuItemControls[ currentMenuItemControls.length - 1 ].container
+						.addClass( 'move-down-disabled' )
+						.toggleClass( 'move-up-disabled', 1 === currentMenuItemControls.length );
+				}
+			};
+
+			reflowRecursively( {
+				menuItemControls: menuItemControls,
+				currentParent: 0,
+				currentDepth: 0,
+				currentAbsolutePosition: 0
+			} );
+
+			menuControl.updateInvitationVisibility( menuItemControls );
+			menuControl.container.find( '.reorder-toggle' ).toggle( menuItemControls.length > 1 );
+		},
+
+		/**
+		 * Note that this function gets debounced so that when a lot of setting
+		 * changes are made at once, for instance when moving a menu item that
+		 * has child items, this function will only be called once all of the
+		 * settings have been updated.
+		 */
+		debouncedReflowMenuItems: _.debounce( function() {
+			this.reflowMenuItems.apply( this, arguments );
+		}, 0 ),
+
+		/**
+		 * Add a new item to this menu.
+		 *
+		 * @param {object} item - Value for the nav_menu_item setting to be created.
+		 * @returns {wp.customize.Menus.controlConstructor.nav_menu_item} The newly-created nav_menu_item control instance.
+		 */
+		addItemToMenu: function( item ) {
+			var menuControl = this, customizeId, settingArgs, setting, menuItemControl, placeholderId, position = 0, priority = 10;
+
+			_.each( menuControl.getMenuItemControls(), function( control ) {
+				if ( false === control.setting() ) {
+					return;
+				}
+				priority = Math.max( priority, control.priority() );
+				if ( 0 === control.setting().menu_item_parent ) {
+					position = Math.max( position, control.setting().position );
+				}
+			});
+			position += 1;
+			priority += 1;
+
+			item = $.extend(
+				{},
+				api.Menus.data.defaultSettingValues.nav_menu_item,
+				item,
+				{
+					nav_menu_term_id: menuControl.params.menu_id,
+					original_title: item.title,
+					position: position
+				}
+			);
+			delete item.id; // only used by Backbone
+
+			placeholderId = api.Menus.generatePlaceholderAutoIncrementId();
+			customizeId = 'nav_menu_item[' + String( placeholderId ) + ']';
+			settingArgs = {
+				type: 'nav_menu_item',
+				transport: api.Menus.data.settingTransport,
+				previewer: api.previewer
+			};
+			setting = api.create( customizeId, customizeId, {}, settingArgs );
+			setting.set( item ); // Change from initial empty object to actual item to mark as dirty.
+
+			// Add the menu item control.
+			menuItemControl = new api.controlConstructor.nav_menu_item( customizeId, {
+				type: 'nav_menu_item',
+				section: menuControl.id,
+				priority: priority,
+				settings: {
+					'default': customizeId
+				},
+				menu_item_id: placeholderId
+			} );
+
+			api.control.add( menuItemControl );
+			setting.preview();
+			menuControl.debouncedReflowMenuItems();
+
+			wp.a11y.speak( api.Menus.data.l10n.itemAdded );
+
+			return menuItemControl;
+		},
+
+		/**
+		 * Show an invitation to add new menu items when there are no menu items.
+		 *
+		 * @since 4.9.0
+		 *
+		 * @param {wp.customize.controlConstructor.nav_menu_item[]} optionalMenuItemControls
+		 */
+		updateInvitationVisibility: function ( optionalMenuItemControls ) {
+			var menuItemControls = optionalMenuItemControls || this.getMenuItemControls();
+
+			this.container.find( '.new-menu-item-invitation' ).toggle( menuItemControls.length === 0 );
+		}
+	} );
+
+	/**
+	 * wp.customize.Menus.NewMenuControl
+	 *
+	 * Customizer control for creating new menus and handling deletion of existing menus.
+	 * Note that 'new_menu' must match the WP_Customize_New_Menu_Control::$type.
+	 *
+	 * @constructor
+	 * @augments wp.customize.Control
+	 * @deprecated 4.9.0 This class is no longer used due to new menu creation UX.
+	 */
+	api.Menus.NewMenuControl = api.Control.extend({
+
+		/**
+		 * Initialize.
+		 *
+		 * @deprecated 4.9.0
+		 */
+		initialize: function() {
+			if ( 'undefined' !== typeof console && console.warn ) {
+				console.warn( '[DEPRECATED] wp.customize.NewMenuControl will be removed. Please use wp.customize.Menus.createNavMenu() instead.' );
+			}
+			api.Control.prototype.initialize.apply( this, arguments );
+		},
+
+		/**
+		 * Set up the control.
+		 *
+		 * @deprecated 4.9.0
+		 */
+		ready: function() {
+			this._bindHandlers();
+		},
+
+		_bindHandlers: function() {
+			var self = this,
+				name = $( '#customize-control-new_menu_name input' ),
+				submit = $( '#create-new-menu-submit' );
+			name.on( 'keydown', function( event ) {
+				if ( 13 === event.which ) { // Enter.
+					self.submit();
+				}
+			} );
+			submit.on( 'click', function( event ) {
+				self.submit();
+				event.stopPropagation();
+				event.preventDefault();
+			} );
+		},
+
+		/**
+		 * Create the new menu with the name supplied.
+		 *
+		 * @deprecated 4.9.0
+		 */
+		submit: function() {
+
+			var control = this,
+				container = control.container.closest( '.accordion-section-new-menu' ),
+				nameInput = container.find( '.menu-name-field' ).first(),
+				name = nameInput.val(),
+				menuSection;
+
+			if ( ! name ) {
+				nameInput.addClass( 'invalid' );
+				nameInput.focus();
+				return;
+			}
+
+			menuSection = api.Menus.createNavMenu( name );
+
+			// Clear name field.
+			nameInput.val( '' );
+			nameInput.removeClass( 'invalid' );
+
+			wp.a11y.speak( api.Menus.data.l10n.menuAdded );
+
+			// Focus on the new menu section.
+			menuSection.focus();
+		}
+	});
+
+	/**
+	 * Extends wp.customize.controlConstructor with control constructor for
+	 * menu_location, menu_item, nav_menu, and new_menu.
+	 */
+	$.extend( api.controlConstructor, {
+		nav_menu_location: api.Menus.MenuLocationControl,
+		nav_menu_item: api.Menus.MenuItemControl,
+		nav_menu: api.Menus.MenuControl,
+		nav_menu_name: api.Menus.MenuNameControl,
+		new_menu: api.Menus.NewMenuControl, // @todo Remove in 5.0. See #42364.
+		nav_menu_locations: api.Menus.MenuLocationsControl,
+		nav_menu_auto_add: api.Menus.MenuAutoAddControl
+	});
+
+	/**
+	 * Extends wp.customize.panelConstructor with section constructor for menus.
+	 */
+	$.extend( api.panelConstructor, {
+		nav_menus: api.Menus.MenusPanel
+	});
+
+	/**
+	 * Extends wp.customize.sectionConstructor with section constructor for menu.
+	 */
+	$.extend( api.sectionConstructor, {
+		nav_menu: api.Menus.MenuSection,
+		new_menu: api.Menus.NewMenuSection
+	});
+
+	/**
+	 * Init Customizer for menus.
+	 */
+	api.bind( 'ready', function() {
+
+		// Set up the menu items panel.
+		api.Menus.availableMenuItemsPanel = new api.Menus.AvailableMenuItemsPanelView({
+			collection: api.Menus.availableMenuItems
+		});
+
+		api.bind( 'saved', function( data ) {
+			if ( data.nav_menu_updates || data.nav_menu_item_updates ) {
+				api.Menus.applySavedData( data );
+			}
+		} );
+
+		/*
+		 * Reset the list of posts created in the customizer once published.
+		 * The setting is updated quietly (bypassing events being triggered)
+		 * so that the customized state doesn't become immediately dirty.
+		 */
+		api.state( 'changesetStatus' ).bind( function( status ) {
+			if ( 'publish' === status ) {
+				api( 'nav_menus_created_posts' )._value = [];
+			}
+		} );
+
+		// Open and focus menu control.
+		api.previewer.bind( 'focus-nav-menu-item-control', api.Menus.focusMenuItemControl );
+	} );
+
+	/**
+	 * When customize_save comes back with a success, make sure any inserted
+	 * nav menus and items are properly re-added with their newly-assigned IDs.
+	 *
+	 * @param {object} data
+	 * @param {array} data.nav_menu_updates
+	 * @param {array} data.nav_menu_item_updates
+	 */
+	api.Menus.applySavedData = function( data ) {
+
+		var insertedMenuIdMapping = {}, insertedMenuItemIdMapping = {};
+
+		_( data.nav_menu_updates ).each(function( update ) {
+			var oldCustomizeId, newCustomizeId, customizeId, oldSetting, newSetting, setting, settingValue, oldSection, newSection, wasSaved, widgetTemplate, navMenuCount, shouldExpandNewSection;
+			if ( 'inserted' === update.status ) {
+				if ( ! update.previous_term_id ) {
+					throw new Error( 'Expected previous_term_id' );
+				}
+				if ( ! update.term_id ) {
+					throw new Error( 'Expected term_id' );
+				}
+				oldCustomizeId = 'nav_menu[' + String( update.previous_term_id ) + ']';
+				if ( ! api.has( oldCustomizeId ) ) {
+					throw new Error( 'Expected setting to exist: ' + oldCustomizeId );
+				}
+				oldSetting = api( oldCustomizeId );
+				if ( ! api.section.has( oldCustomizeId ) ) {
+					throw new Error( 'Expected control to exist: ' + oldCustomizeId );
+				}
+				oldSection = api.section( oldCustomizeId );
+
+				settingValue = oldSetting.get();
+				if ( ! settingValue ) {
+					throw new Error( 'Did not expect setting to be empty (deleted).' );
+				}
+				settingValue = $.extend( _.clone( settingValue ), update.saved_value );
+
+				insertedMenuIdMapping[ update.previous_term_id ] = update.term_id;
+				newCustomizeId = 'nav_menu[' + String( update.term_id ) + ']';
+				newSetting = api.create( newCustomizeId, newCustomizeId, settingValue, {
+					type: 'nav_menu',
+					transport: api.Menus.data.settingTransport,
+					previewer: api.previewer
+				} );
+
+				shouldExpandNewSection = oldSection.expanded();
+				if ( shouldExpandNewSection ) {
+					oldSection.collapse();
+				}
+
+				// Add the menu section.
+				newSection = new api.Menus.MenuSection( newCustomizeId, {
+					panel: 'nav_menus',
+					title: settingValue.name,
+					customizeAction: api.Menus.data.l10n.customizingMenus,
+					type: 'nav_menu',
+					priority: oldSection.priority.get(),
+					menu_id: update.term_id
+				} );
+
+				// Add new control for the new menu.
+				api.section.add( newSection );
+
+				// Update the values for nav menus in Navigation Menu controls.
+				api.control.each( function( setting ) {
+					if ( ! setting.extended( api.controlConstructor.widget_form ) || 'nav_menu' !== setting.params.widget_id_base ) {
+						return;
+					}
+					var select, oldMenuOption, newMenuOption;
+					select = setting.container.find( 'select' );
+					oldMenuOption = select.find( 'option[value=' + String( update.previous_term_id ) + ']' );
+					newMenuOption = select.find( 'option[value=' + String( update.term_id ) + ']' );
+					newMenuOption.prop( 'selected', oldMenuOption.prop( 'selected' ) );
+					oldMenuOption.remove();
+				} );
+
+				// Delete the old placeholder nav_menu.
+				oldSetting.callbacks.disable(); // Prevent setting triggering Customizer dirty state when set.
+				oldSetting.set( false );
+				oldSetting.preview();
+				newSetting.preview();
+				oldSetting._dirty = false;
+
+				// Remove nav_menu section.
+				oldSection.container.remove();
+				api.section.remove( oldCustomizeId );
+
+				// Update the nav_menu widget to reflect removed placeholder menu.
+				navMenuCount = 0;
+				api.each(function( setting ) {
+					if ( /^nav_menu\[/.test( setting.id ) && false !== setting() ) {
+						navMenuCount += 1;
+					}
+				});
+				widgetTemplate = $( '#available-widgets-list .widget-tpl:has( input.id_base[ value=nav_menu ] )' );
+				widgetTemplate.find( '.nav-menu-widget-form-controls:first' ).toggle( 0 !== navMenuCount );
+				widgetTemplate.find( '.nav-menu-widget-no-menus-message:first' ).toggle( 0 === navMenuCount );
+				widgetTemplate.find( 'option[value=' + String( update.previous_term_id ) + ']' ).remove();
+
+				// Update the nav_menu_locations[...] controls to remove the placeholder menus from the dropdown options.
+				wp.customize.control.each(function( control ){
+					if ( /^nav_menu_locations\[/.test( control.id ) ) {
+						control.container.find( 'option[value=' + String( update.previous_term_id ) + ']' ).remove();
+					}
+				});
+
+				// Update nav_menu_locations to reference the new ID.
+				api.each( function( setting ) {
+					var wasSaved = api.state( 'saved' ).get();
+					if ( /^nav_menu_locations\[/.test( setting.id ) && setting.get() === update.previous_term_id ) {
+						setting.set( update.term_id );
+						setting._dirty = false; // Not dirty because this is has also just been done on server in WP_Customize_Nav_Menu_Setting::update().
+						api.state( 'saved' ).set( wasSaved );
+						setting.preview();
+					}
+				} );
+
+				if ( shouldExpandNewSection ) {
+					newSection.expand();
+				}
+			} else if ( 'updated' === update.status ) {
+				customizeId = 'nav_menu[' + String( update.term_id ) + ']';
+				if ( ! api.has( customizeId ) ) {
+					throw new Error( 'Expected setting to exist: ' + customizeId );
+				}
+
+				// Make sure the setting gets updated with its sanitized server value (specifically the conflict-resolved name).
+				setting = api( customizeId );
+				if ( ! _.isEqual( update.saved_value, setting.get() ) ) {
+					wasSaved = api.state( 'saved' ).get();
+					setting.set( update.saved_value );
+					setting._dirty = false;
+					api.state( 'saved' ).set( wasSaved );
+				}
+			}
+		} );
+
+		// Build up mapping of nav_menu_item placeholder IDs to inserted IDs.
+		_( data.nav_menu_item_updates ).each(function( update ) {
+			if ( update.previous_post_id ) {
+				insertedMenuItemIdMapping[ update.previous_post_id ] = update.post_id;
+			}
+		});
+
+		_( data.nav_menu_item_updates ).each(function( update ) {
+			var oldCustomizeId, newCustomizeId, oldSetting, newSetting, settingValue, oldControl, newControl;
+			if ( 'inserted' === update.status ) {
+				if ( ! update.previous_post_id ) {
+					throw new Error( 'Expected previous_post_id' );
+				}
+				if ( ! update.post_id ) {
+					throw new Error( 'Expected post_id' );
+				}
+				oldCustomizeId = 'nav_menu_item[' + String( update.previous_post_id ) + ']';
+				if ( ! api.has( oldCustomizeId ) ) {
+					throw new Error( 'Expected setting to exist: ' + oldCustomizeId );
+				}
+				oldSetting = api( oldCustomizeId );
+				if ( ! api.control.has( oldCustomizeId ) ) {
+					throw new Error( 'Expected control to exist: ' + oldCustomizeId );
+				}
+				oldControl = api.control( oldCustomizeId );
+
+				settingValue = oldSetting.get();
+				if ( ! settingValue ) {
+					throw new Error( 'Did not expect setting to be empty (deleted).' );
+				}
+				settingValue = _.clone( settingValue );
+
+				// If the parent menu item was also inserted, update the menu_item_parent to the new ID.
+				if ( settingValue.menu_item_parent < 0 ) {
+					if ( ! insertedMenuItemIdMapping[ settingValue.menu_item_parent ] ) {
+						throw new Error( 'inserted ID for menu_item_parent not available' );
+					}
+					settingValue.menu_item_parent = insertedMenuItemIdMapping[ settingValue.menu_item_parent ];
+				}
+
+				// If the menu was also inserted, then make sure it uses the new menu ID for nav_menu_term_id.
+				if ( insertedMenuIdMapping[ settingValue.nav_menu_term_id ] ) {
+					settingValue.nav_menu_term_id = insertedMenuIdMapping[ settingValue.nav_menu_term_id ];
+				}
+
+				newCustomizeId = 'nav_menu_item[' + String( update.post_id ) + ']';
+				newSetting = api.create( newCustomizeId, newCustomizeId, settingValue, {
+					type: 'nav_menu_item',
+					transport: api.Menus.data.settingTransport,
+					previewer: api.previewer
+				} );
+
+				// Add the menu control.
+				newControl = new api.controlConstructor.nav_menu_item( newCustomizeId, {
+					type: 'nav_menu_item',
+					menu_id: update.post_id,
+					section: 'nav_menu[' + String( settingValue.nav_menu_term_id ) + ']',
+					priority: oldControl.priority.get(),
+					settings: {
+						'default': newCustomizeId
+					},
+					menu_item_id: update.post_id
+				} );
+
+				// Remove old control.
+				oldControl.container.remove();
+				api.control.remove( oldCustomizeId );
+
+				// Add new control to take its place.
+				api.control.add( newControl );
+
+				// Delete the placeholder and preview the new setting.
+				oldSetting.callbacks.disable(); // Prevent setting triggering Customizer dirty state when set.
+				oldSetting.set( false );
+				oldSetting.preview();
+				newSetting.preview();
+				oldSetting._dirty = false;
+
+				newControl.container.toggleClass( 'menu-item-edit-inactive', oldControl.container.hasClass( 'menu-item-edit-inactive' ) );
+			}
+		});
+
+		/*
+		 * Update the settings for any nav_menu widgets that had selected a placeholder ID.
+		 */
+		_.each( data.widget_nav_menu_updates, function( widgetSettingValue, widgetSettingId ) {
+			var setting = api( widgetSettingId );
+			if ( setting ) {
+				setting._value = widgetSettingValue;
+				setting.preview(); // Send to the preview now so that menu refresh will use the inserted menu.
+			}
+		});
+	};
+
+	/**
+	 * Focus a menu item control.
+	 *
+	 * @param {string} menuItemId
+	 */
+	api.Menus.focusMenuItemControl = function( menuItemId ) {
+		var control = api.Menus.getMenuItemControl( menuItemId );
+		if ( control ) {
+			control.focus();
+		}
+	};
+
+	/**
+	 * Get the control for a given menu.
+	 *
+	 * @param menuId
+	 * @return {wp.customize.controlConstructor.menus[]}
+	 */
+	api.Menus.getMenuControl = function( menuId ) {
+		return api.control( 'nav_menu[' + menuId + ']' );
+	};
+
+	/**
+	 * Given a menu item ID, get the control associated with it.
+	 *
+	 * @param {string} menuItemId
+	 * @return {object|null}
+	 */
+	api.Menus.getMenuItemControl = function( menuItemId ) {
+		return api.control( menuItemIdToSettingId( menuItemId ) );
+	};
+
+	/**
+	 * @param {String} menuItemId
+	 */
+	function menuItemIdToSettingId( menuItemId ) {
+		return 'nav_menu_item[' + menuItemId + ']';
+	}
+
+	/**
+	 * Apply sanitize_text_field()-like logic to the supplied name, returning a
+	 * "unnammed" fallback string if the name is then empty.
+	 *
+	 * @param {string} name
+	 * @returns {string}
+	 */
+	function displayNavMenuName( name ) {
+		name = name || '';
+		name = $( '<div>' ).text( name ).html(); // Emulate esc_html() which is used in wp-admin/nav-menus.php.
+		name = $.trim( name );
+		return name || api.Menus.data.l10n.unnamed;
+	}
+
+})( wp.customize, wp, jQuery );