Index: includes/form.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/form.inc,v
retrieving revision 1.297
diff -u -r1.297 form.inc
--- includes/form.inc	15 Oct 2008 14:17:26 -0000	1.297
+++ includes/form.inc	17 Oct 2008 22:29:15 -0000
@@ -1515,7 +1515,9 @@
       $element['#attributes']['class'] .= ' collapsed';
     }
   }
-
+  
+  $element['#attributes']['id'] = form_clean_id(drupal_strtolower($element['#title']));
+  
   return '<fieldset' . drupal_attributes($element['#attributes']) . '>' . ($element['#title'] ? '<legend>' . $element['#title'] . '</legend>' : '') . (isset($element['#description']) && $element['#description'] ? '<div class="description">' . $element['#description'] . '</div>' : '') . (!empty($element['#children']) ? $element['#children'] : '') . (isset($element['#value']) ? $element['#value'] : '') . "</fieldset>\n";
 }