diff --git includes/form.inc includes/form.inc
index 97841eb..ca86b10 100644
--- includes/form.inc
+++ includes/form.inc
@@ -328,9 +328,8 @@ function drupal_rebuild_form($form_id, &$form_state, $form_build_id = NULL) {
   drupal_prepare_form($form_id, $form, $form_state);
 
   if (empty($form_state['no_cache'])) {
-    // We cache the form structure so it can be retrieved later for validation.
-    // If $form_state['storage'] is populated, we also cache it so that it can
-    // be used to resume complex multi-step processes.
+    // We cache the form structure and the form state so it can be retrieved
+    // later for validation.
     form_set_cache($form_build_id, $form, $form_state);
   }
 
@@ -396,8 +395,6 @@ function form_state_keys_no_cache() {
   return array(
     // Public properties defined by form constructors and form handlers.
     'always_process',
-    'cache',
-    'no_cache',
     'must_validate',
     'rebuild',
     'redirect',
diff --git modules/simpletest/tests/form_test.module modules/simpletest/tests/form_test.module
index 9b40232..6a4eb9d 100644
--- modules/simpletest/tests/form_test.module
+++ modules/simpletest/tests/form_test.module
@@ -144,6 +144,11 @@ function form_test_validate_form($form, &$form_state) {
     '#type' => 'submit',
     '#value' => 'Save',
   );
+
+  // To simplify this test, enable form caching and use form storage to
+  // remember our alteration.
+  $form_state['cache'] = TRUE;
+  
   return $form;
 }
 
@@ -161,9 +166,6 @@ function form_test_element_validate_name(&$element, &$form_state) {
     $triggered = TRUE;
   }
   if ($form_state['values']['name'] == 'element_validate_access') {
-    // To simplify this test, enable form caching and use form storage to
-    // remember our alteration.
-    $form_state['cache'] = TRUE;
     $form_state['storage']['form_test_name'] = $form_state['values']['name'];
     // Alter the form element.
     $element['#access'] = FALSE;
@@ -453,9 +455,6 @@ function form_test_storage_element_validate_value_cached($element, &$form_state)
   // though.
   if (isset($_REQUEST['cache']) && $form_state['values']['value'] == 'change_title') {
     $form_state['storage']['thing']['changed'] = TRUE;
-    // @todo Fix FAPI to make it unnecessary to explicitly set the cache flag in
-    //   this situation. @see http://drupal.org/node/641356.
-    $form_state['cache'] = TRUE;
   }
 }