--- a/wp/wp-includes/js/wp-lists.js	Mon Jun 08 16:11:51 2015 +0000
+++ b/wp/wp-includes/js/wp-lists.js	Tue Jun 09 03:35:32 2015 +0200
@@ -1,3 +1,4 @@
+/* global ajaxurl, wpAjax */
 (function($) {
 var fs = {add:'ajaxAdd',del:'ajaxDel',dim:'ajaxDim',process:'process',recolor:'recolor'}, wpList;
 
@@ -308,7 +309,11 @@
 	},
 
 	add: function( e, s ) {
-		e = $( $.trim(e) ); // Trim leading whitespaces
+		if ( 'string' == typeof e ) {
+			e = $( $.trim( e ) ); // Trim leading whitespaces
+		} else {
+			e = $( e );
+		}
 
 		var list = $(this), old = false, _s = { pos: 0, id: 0, oldId: null }, ba, ref, color;