--- drupal-cvs/includes/form.inc	2006-04-22 11:00:01.000000000 +0200
+++ drupal-cvs/includes/form.inc	2006-04-23 23:20:56.000000000 +0200
@@ -951,7 +951,7 @@
  *   A themed HTML string representing the hidden form field.
  */
 function theme_hidden($element) {
-  return '<input type="hidden" name="'. $element['#name'] . '" value="'. check_plain($element['#value']) ."\" " . drupal_attributes($element['#attributes']) ." />\n";
+  return '<input type="hidden" name="'. $element['#name'] . '" id="'. $element['#id'] . '" value="'. check_plain($element['#value']) ."\" " . drupal_attributes($element['#attributes']) ." />\n";
 }
 
 /**