diff --git a/modules/simpletest/tests/form.test b/modules/simpletest/tests/form.test
index ce3deab..37b76c6 100644
--- a/modules/simpletest/tests/form.test
+++ b/modules/simpletest/tests/form.test
@@ -1093,19 +1093,26 @@ class FormsElementsVerticalTabsFunctionalTest extends DrupalWebTestCase {
    * 3. They are children of the wrapper with no #group set for any child.
    */
   function testTabsShowForChildOrGroup() {
-    // Test we can see a non-child with #group set.
+    // Tests we can see fieldsets which are not child elements vertical_tabs
+    // form element, but are placed in the set of vertical tabs because of their
+    // #group, like $form['email_admin_created'] in user_admin_settings().
     $this->drupalGet('form_test/vertical-tabs');
     $tab1 = $this->xpath("//div[@class='vertical-tabs-panes']/fieldset[@id='edit-tab1']");
     $this->assertTrue(isset($tab1[0]), 'Non-child with #group found.');
 
-    // Test we can see a child with #group set.
-    $tab3 = $this->xpath("//div[@class='vertical-tabs-panes']/fieldset[@id='edit-tab3']");
-    $this->assertTrue(isset($tab3[0]), 'Child with #group found.');
-
-    // Test we can see children without #group set.
+    // Tests that we can see fieldsets which are child elements of the
+    // vertical_tabs form element, and are placed in the set of vertical tabs
+    // simply because they're child elements.
     $this->drupalGet('form_test/vertical-tabs-2');
     $tab2 = $this->xpath("//div[@class='vertical-tabs-panes']/fieldset[@id='edit-tab2']");
     $this->assertTrue(isset($tab2[0]), 'Children with no #group found.');
+
+    // Tests that we can see fieldsets which are BOTH child elements of the
+    // vertical_tabs form element AND have their #group set, like
+    // $form['visibility']['path'] in block_admin_configure().
+    $this->drupalGet('form_test/vertical-tabs-3');
+    $tab2 = $this->xpath("//div[@class='vertical-tabs-panes']/fieldset[@id='edit-tab2']");
+    $this->assertTrue(isset($tab2[0]), 'Child with #group found.');
   }
 }
 
diff --git a/modules/simpletest/tests/form_test.module b/modules/simpletest/tests/form_test.module
index ea204c3..2dbf259 100644
--- a/modules/simpletest/tests/form_test.module
+++ b/modules/simpletest/tests/form_test.module
@@ -90,6 +90,14 @@ function form_test_menu() {
     'type' => MENU_CALLBACK,
   );
 
+  $items['form_test/vertical-tabs-3'] = array(
+    'title' => 'Vertical tabs tests',
+    'page callback' => 'drupal_get_form',
+    'page arguments' => array('_form_test_vertical_tabs_3_form'),
+    'access arguments' => array('access content'),
+    'type' => MENU_CALLBACK,
+  );
+
   $items['form_test/form-storage'] = array(
     'title' => 'Form storage test',
     'page callback' => 'drupal_get_form',
@@ -688,7 +696,7 @@ function _form_test_tableselect_js_select_form($form, $form_state, $action) {
 }
 
 /**
- * Tests functionality of vertical tabs.
+ * Tests functionality of vertical tabs - non-children with an explicit #group.
  */
 function _form_test_vertical_tabs_form($form, &$form_state) {
   $form['vertical_tabs'] = array(
@@ -716,17 +724,6 @@ function _form_test_vertical_tabs_form($form, &$form_state) {
     '#title' => t('Field 2'),
     '#type' => 'textfield',
   );
-  $form['vertical_tabs']['tab3'] = array(
-    '#type' => 'fieldset',
-    '#title' => t('Tab 3'),
-    '#collapsible' => TRUE,
-    '#group' => 'vertical_tabs',
-    '#access' => user_access('access vertical_tab_test tabs')
-  );
-  $form['vertical_tabs']['tab3']['field3'] = array(
-    '#title' => t('Field 3'),
-    '#type' => 'textfield',
-  );
   return $form;
 }
 
@@ -761,6 +758,38 @@ function _form_test_vertical_tabs_2_form($form, &$form_state) {
 }
 
 /**
+ * Tests functionality of vertical tabs - children with an explicit #group.
+ */
+function _form_test_vertical_tabs_3_form($form, &$form_state) {
+  $form['vertical_tabs'] = array(
+    '#type' => 'vertical_tabs',
+  );
+  $form['vertical_tabs']['tab1'] = array(
+    '#type' => 'fieldset',
+    '#title' => t('Tab 1'),
+    '#collapsible' => TRUE,
+    '#access' => user_access('access vertical_tab_test tabs'),
+    '#group' => 'vertical_tabs',
+  );
+  $form['vertical_tabs']['tab1']['field1'] = array(
+    '#title' => t('Field 1'),
+    '#type' => 'textfield',
+  );
+  $form['vertical_tabs']['tab2'] = array(
+    '#type' => 'fieldset',
+    '#title' => t('Tab 2'),
+    '#collapsible' => TRUE,
+    '#access' => user_access('access vertical_tab_test tabs'),
+    '#group' => 'vertical_tabs',
+  );
+  $form['vertical_tabs']['tab2']['field2'] = array(
+    '#title' => t('Field 2'),
+    '#type' => 'textfield',
+  );
+  return $form;
+}
+
+/**
  * A multistep form for testing the form storage.
  *
  * It uses two steps for editing a virtual "thing". Any changes to it are saved