diff -u b/core/lib/Drupal/Core/Entity/EntityListController.php b/core/lib/Drupal/Core/Entity/EntityListController.php
--- b/core/lib/Drupal/Core/Entity/EntityListController.php
+++ b/core/lib/Drupal/Core/Entity/EntityListController.php
@@ -108,6 +108,9 @@
       $operations['delete'] = array(
         'title' => $this->t('Delete'),
         'href' => $uri['path'] . '/delete',
+        'ajax' => array(
+          'accepts' => 'application/vnd.drupal-modal',
+        ),
         'options' => $uri['options'],
         'weight' => 100,
       );
@@ -127,9 +130,6 @@
       $operations['delete'] = array(
         'title' => $this->t('Delete'),
         'href' => $uri['path'] . '/delete',
-        'ajax' => array(
-          'accepts' => 'application/vnd.drupal-modal',
-        ),
         'options' => $uri['options'],
         'weight' => 100,
       );
only in patch2:
unchanged:
--- a/core/modules/search/lib/Drupal/search/Form/SearchPageFormBase.php
+++ b/core/modules/search/lib/Drupal/search/Form/SearchPageFormBase.php
@@ -167,7 +167,7 @@ public function submit(array $form, array &$form_state) {
     parent::submit($form, $form_state);
 
     if ($this->plugin instanceof PluginFormInterface) {
-      $this->plugin->submitConfigurationForm($form, $form_state);
+      $this->entity->getPlugin()->submitConfigurationForm($form, $form_state);
     }
     return $this->entity;
   }