Ticket #20086: 20086.diff

wp-admin/js/tags.dev.js

@@ -37 +37 @@
                         var res = wpAjax.parseAjaxResponse(r, 'ajax-response');
                         if ( ! res )
                                 return;
+                                
+                        if( res.errors )
+                                return false;
 
                         var parent = form.find('select#parent').val();