diff --git a/core/lib/Drupal/Core/Entity/EntityManager.php b/core/lib/Drupal/Core/Entity/EntityManager.php
index a9c0dd3..652af59 100644
--- a/core/lib/Drupal/Core/Entity/EntityManager.php
+++ b/core/lib/Drupal/Core/Entity/EntityManager.php
@@ -418,26 +418,15 @@ public function getAllBundleInfo() {
    */
   public function getEntityTypeLabels($group = FALSE) {
     $options = array();
-    $groups = array();
-    $group_options = array();
     foreach ($this->getDefinitions() as $entity_type => $definition) {
-      if ($group) {
-        $group_label = $definition->getGroupLabel() ?: $this->translationManager->translate('Content', array(), array('context' => 'Entity type group'));
-        $groups[$group_label] = $group_label;
-        $group_options[$group_label][$entity_type] = $definition->getLabel();
+      if ($group && ($group_label = $definition->getGroupLabel())) {
+        $options[$group_label][$entity_type] = $definition->getLabel();
       }
       else {
         $options[$entity_type] = $definition->getLabel();
       }
     }
-
-    if ($group) {
-      natcasesort($groups);
-      foreach ($groups as $group_label) {
-        natcasesort($group_options[$group_label]);
-        $options[$group_label] = $group_options[$group_label];
-      }
-    }
+    array_multisort($options);
 
     return $options;
   }
diff --git a/core/modules/entity_reference/lib/Drupal/entity_reference/Tests/EntityReferenceAdminTest.php b/core/modules/entity_reference/lib/Drupal/entity_reference/Tests/EntityReferenceAdminTest.php
index 37cf7bb..54eea8f 100644
--- a/core/modules/entity_reference/lib/Drupal/entity_reference/Tests/EntityReferenceAdminTest.php
+++ b/core/modules/entity_reference/lib/Drupal/entity_reference/Tests/EntityReferenceAdminTest.php
@@ -42,7 +42,7 @@ protected function assertFieldSelectOptions($name, $expected_options) {
     if ($fields) {
       $field = $fields[0];
       $options = $this->getAllOptionsList($field);
-      return $this->assertIdentical($options, $expected_options);
+      return $this->assertIdentical(sort($options), sort($expected_options));
     }
     else {
       return $this->fail(t('Unable to find field @name', array('@name' => $name)));
@@ -58,7 +58,11 @@ protected function getAllOptionsList($element) {
     foreach ($element->option as $option) {
       $options[] = (string) $option['value'];
     }
-    // TODO: support optgroup.
+
+    if (isset($element->optgroup)) {
+      $options += $this->getAllOptionsList($element->optgroup);
+    }
+
     return $options;
   }
 
@@ -76,9 +80,7 @@ public function testFieldAdminHandler() {
     $this->assertFieldByName('field[settings][target_type]', 'node');
 
     // Check that all entity types can be referenced.
-    foreach (\Drupal::entityManager()->getDefinitions() as $entity_type_id => $entity_type) {
-      $this->assertFieldByXPath("//select[@name='field[settings][target_type]']/option[@value='" . $entity_type_id . "']");
-    }
+    $this->assertFieldSelectOptions('field[settings][target_type]', array_keys(\Drupal::entityManager()->getDefinitions()));
 
     // Second step: 'Instance settings' form.
     $this->drupalPostForm(NULL, array(), t('Save field settings'));
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
index a442dd0..ebc4a97 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
@@ -3041,7 +3041,7 @@ protected function assertFieldByXPath($xpath, $value = NULL, $message = '', $gro
             // Input element with correct value.
             $found = TRUE;
           }
-          elseif (isset($field->option)) {
+          elseif (isset($field->option) || isset($field->optgroup)) {
             // Select element found.
             if ($this->getSelectedItem($field) == $value) {
               $found = TRUE;