diff --git a/core/lib/Drupal/Core/Form/FormBuilder.php b/core/lib/Drupal/Core/Form/FormBuilder.php
index cd8ffbc..9dd8bd5 100644
--- a/core/lib/Drupal/Core/Form/FormBuilder.php
+++ b/core/lib/Drupal/Core/Form/FormBuilder.php
@@ -738,7 +738,7 @@ public function prepareForm($form_id, &$form, &$form_state) {
     }
 
     $form += $this->getElementInfo('form');
-    $form += array('#tree' => FALSE, '#parents' => array());
+    $form += array('#tree' => TRUE, '#parents' => array());
 
     if (!isset($form['#validate'])) {
       // Ensure that modules can rely on #validate being set.