Index: date/date_elements.inc
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/date/date/date_elements.inc,v
retrieving revision 1.46.2.2.2.67
diff -u -p -r1.46.2.2.2.67 date_elements.inc
--- date/date_elements.inc	5 Mar 2010 15:02:47 -0000	1.46.2.2.2.67
+++ date/date_elements.inc	18 May 2010 20:56:34 -0000
@@ -573,7 +573,9 @@ function theme_date_combo($element) {
     '#collapsible' => FALSE,
     '#collapsed' => FALSE,
     '#description' => $element['#fieldset_description'],
-    '#attributes' => array(),
+    '#attributes' => array(
+      'class' => $field['field_name'] . '-field-wrapper',
+    ),
   );
   return theme('fieldset', $fieldset);
 }