diff --git a/field_group.js b/field_group.js
index eef6aaa..67d6b64 100644
--- a/field_group.js
+++ b/field_group.js
@@ -20,7 +20,7 @@ Drupal.FieldGroup.Effects.processFieldset = {
   execute: function (context, settings, type) {
     if (type == 'form') {
       // Add required fields mark to any fieldsets containing required fields
-      $('fieldset.fieldset', context).once('fieldgroup-effects', function(i) {
+      $('fieldset.fieldset:not(.horizontal-tabs-pane,.vertical-tabs-pane)', context).once('fieldgroup-effects', function(i) {
         if ($(this).is('.required-fields') && $(this).find('.form-required').length > 0) {
           $('legend span.fieldset-legend', $(this)).eq(0).append(' ').append($('.form-required').eq(0).clone());
         }