diff --git a/src/wp-includes/js/customize-preview-nav-menus.js b/src/wp-includes/js/customize-preview-nav-menus.js
index 27c525107b..6745b41be8 100644
--- a/src/wp-includes/js/customize-preview-nav-menus.js
+++ b/src/wp-includes/js/customize-preview-nav-menus.js
@@ -419,7 +419,7 @@ wp.customize.navMenusPreview = wp.customize.MenusCustomizerPreview = ( function(
 				return;
 			}
 
-			navMenuItemParts = $( this ).attr( 'class' ).match( /(?:^|\s)menu-item-(\d+)(?:\s|$)/ );
+			navMenuItemParts = $( this ).attr( 'class' ).match( /(?:^|\s)menu-item-(-?\d+)(?:\s|$)/ );
 			if ( navMenuItemParts ) {
 				e.preventDefault();
 				e.stopPropagation(); // Make sure a sub-nav menu item will get focused instead of parent items.