Index: wp-admin/js/nav-menu.js
===================================================================
--- wp-admin/js/nav-menu.js	(revision 24572)
+++ wp-admin/js/nav-menu.js	(working copy)
@@ -930,7 +930,7 @@
 		 * @param object req The request arguments.
 		 */
 		addMenuItemToBottom : function( menuMarkup, req ) {
-			$(menuMarkup).hideAdvancedMenuItemFields().appendTo( api.targetList );
+			$( $.trim(menuMarkup) ).hideAdvancedMenuItemFields().appendTo( api.targetList );
 			api.refreshKeyboardAccessibility();
 			api.refreshAdvancedAccessibility();
 		},
Index: wp-includes/js/wp-lists.js
===================================================================
--- wp-includes/js/wp-lists.js	(revision 24572)
+++ wp-includes/js/wp-lists.js	(working copy)
@@ -208,7 +208,7 @@
 					s.delAfter( rres, _s );
 				}).dequeue();
 			}
-		}
+		};
 
 		$.ajax( s );
 		return false;
@@ -308,7 +308,7 @@
 	},
 
 	add: function( e, s ) {
-		e = $(e);
+		e = $( $.trim(e) );
 
 		var list = $(this), old = false, _s = { pos: 0, id: 0, oldId: null }, ba, ref, color;