Index: form.inc
===================================================================
--- form.inc	(revision 11)
+++ form.inc	(working copy)
@@ -1541,11 +1541,8 @@
  * @ingroup themeable
  */
 function theme_radios($element) {
-  $class = 'form-radios';
-  if (isset($element['#attributes']['class'])) {
-    $class .= ' '. $element['#attributes']['class'];
-  }
-  $element['#children'] = '<div class="'. $class .'">'. (!empty($element['#children']) ? $element['#children'] : '') .'</div>';
+  _form_set_class($element, array('form-radios'));
+  $element['#children'] = '<div '. drupal_attributes($element['#attributes']) .'">'. (!empty($element['#children']) ? $element['#children'] : '') .'</div>';
   if ($element['#title'] || $element['#description']) {
     unset($element['#id']);
     return theme('form_element', $element, $element['#children']);
@@ -1878,11 +1875,8 @@
  * @ingroup themeable
  */
 function theme_checkboxes($element) {
-  $class = 'form-checkboxes';
-  if (isset($element['#attributes']['class'])) {
-    $class .= ' '. $element['#attributes']['class'];
-  }
-  $element['#children'] = '<div class="'. $class .'">'. (!empty($element['#children']) ? $element['#children'] : '') .'</div>';
+  _form_set_class($element, array('form-checkboxes'));
+  $element['#children'] = '<div '. drupal_attributes($element['#attributes']) .'">'. (!empty($element['#children']) ? $element['#children'] : '') .'</div>';
   if ($element['#title'] || $element['#description']) {
     unset($element['#id']);
     return theme('form_element', $element, $element['#children']);