diff --git a/includes/form.inc b/includes/form.inc
index b29efcc..bdb86e4 100644
--- a/includes/form.inc
+++ b/includes/form.inc
@@ -573,9 +573,7 @@ function drupal_prepare_form($form_id, &$form, &$form_state) {
  *   not be repeated in the submission step.
  */
 function drupal_validate_form($form_id, $form, &$form_state) {
-  static $validated_forms = array();
-
-  if (isset($validated_forms[$form_id])) {
+  if (!empty($form_state['validated'])) {
     return;
   }
 
@@ -589,7 +587,7 @@ function drupal_validate_form($form_id, $form, &$form_state) {
   }
 
   _form_validate($form, $form_state, $form_id);
-  $validated_forms[$form_id] = TRUE;
+  $form_state['validated'] = TRUE;
 }
 
 /**