diff --git a/core/modules/field_ui/lib/Drupal/field_ui/DisplayOverview.php b/core/modules/field_ui/lib/Drupal/field_ui/DisplayOverview.php
index 94e115f..870df32 100644
--- a/core/modules/field_ui/lib/Drupal/field_ui/DisplayOverview.php
+++ b/core/modules/field_ui/lib/Drupal/field_ui/DisplayOverview.php
@@ -43,7 +43,7 @@ public function buildForm(array $form, array &$form_state, $entity_type = NULL,
       $this->mode = $this->getRequest()->attributes->get('view_mode_name');
     }
 
-    parent::buildForm($form, $form_state, $entity_type, $bundle);
+    return parent::buildForm($form, $form_state, $entity_type, $bundle);
   }
 
   /**
diff --git a/core/modules/field_ui/lib/Drupal/field_ui/FormDisplayOverview.php b/core/modules/field_ui/lib/Drupal/field_ui/FormDisplayOverview.php
index 19cf261..0c4877c 100644
--- a/core/modules/field_ui/lib/Drupal/field_ui/FormDisplayOverview.php
+++ b/core/modules/field_ui/lib/Drupal/field_ui/FormDisplayOverview.php
@@ -43,7 +43,7 @@ public function buildForm(array $form, array &$form_state, $entity_type = NULL,
       $this->mode = $this->getRequest()->attributes->get('form_mode_name');
     }
 
-    parent::buildForm($form, $form_state, $entity_type, $bundle);
+    return parent::buildForm($form, $form_state, $entity_type, $bundle);
   }
 
   /**