Index: wp-admin/js/customize-controls.js
===================================================================
--- wp-admin/js/customize-controls.js	(revision 33702)
+++ wp-admin/js/customize-controls.js	(working copy)
@@ -1497,7 +1497,7 @@
 		 * @param {Callback} args.completeCallback
 		 */
 		onChangeActive: function ( active, args ) {
-			if ( ! $.contains( document, this.container ) ) {
+			if ( this.container[0] && ! $.contains( document, this.container[0] ) ) {
 				// jQuery.fn.slideUp is not hiding an element if it is not in the DOM
 				this.container.toggle( active );
 				if ( args.completeCallback ) {