Minor fix

It does not worked for me in popup window.

modules/backend/widgets/form/assets/js/october.form.js

@@ -146,7 +146,7 @@
 
         this.toggleEmptyTabsTimer = window.setTimeout(function() {
 
-            var tabControl = $('[data-control=tab]', this.$el),
+            var tabControl = $('[data-control=tab]', self.$el),
                 tabContainer = $('.nav-tabs', tabControl)
 
             if (!tabControl.length || !$.contains(form.get(0), tabControl.get(0)))
@@ -233,4 +233,4 @@
         $('[data-control="formwidget"]').formWidget();
     })
 
-}(window.jQuery);
+}(window.jQuery);