Fatal error: Uncaught Error: Class "Drupal\Core\Entity\EntityDeleteForm" not found in /home/www/drupal8/test/core/modules/field_ui/src/Form/EntityDisplayModeDeleteForm.php:12 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/field_ui/src/Form/EntityDisplayModeDeleteForm.php on line 12