Index: tabs.theme.inc
===================================================================
--- tabs.theme.inc	(revision 2849)
+++ tabs.theme.inc	(working copy)
@@ -12,7 +12,7 @@
  * @themable
  */
 function theme_tabset($element) {
-  $output = '<div id="tabs-'. $element['#tabset_name'] .'"'. drupal_attributes($element['#attributes']) .'>';
+  $output = '<div id="'. $element['#tabset_name'] .'"'. drupal_attributes($element['#attributes']) .'>';
   $output .= '<ul class="tabs clear-block">';
   foreach (element_children($element) as $key) {
     if (isset($element[$key]['#type']) && $element[$key]['#type'] == 'tabpage') {
Index: tabs.module
===================================================================
--- tabs.module	(revision 2849)
+++ tabs.module	(working copy)
@@ -48,7 +48,7 @@
 function tabs_pre_render_tabset($element) {
   tabs_load();
   // Assign a name, reading from the first parent (the key of this tabset element).
-  $name = $element['#tabset_name'] = form_clean_id(isset($element['#tabset_name']) && $element['#tabset_name'] ? $element['#tabset_name'] : (isset($element['#parents']) && count($element['#parents']) ? $element['#parents'][0] : 'tabset'));
+  $name = $element['#tabset_name'] = form_clean_id('tabs-' . (isset($element['#tabset_name']) && $element['#tabset_name'] ? $element['#tabset_name'] : (isset($element['#parents']) && count($element['#parents']) ? $element['#parents'][0] : 'tabset')));
 
   // Add class.
   if (!isset($element['#attributes'])) {
@@ -81,7 +81,7 @@
       }
       // If the tab_name is still empty, set one.
       if (!isset($element[$key]['#tab_name']) || empty($element[$key]['#tab_name'])) {
-        $element[$key]['#tab_name'] = 'tabs-' . $element['#tabset_name'] . '-' . $index;
+        $element[$key]['#tab_name'] = $element['#tabset_name'] . '-' . $index;
       }
       $element[$key]['#tab_name'] = form_clean_id($element[$key]['#tab_name']);
       if (!isset($element[$key]['#attributes'])) {