issue #3191727: Focus states on mobile second level navigation items fixed

Closes #3191727

core/modules/views/src/Controller/ViewAjaxController.php

@@ -214,6 +214,10 @@ public function ajaxView(Request $request) {
         $response->addCommand(new PrependCommand(".js-view-dom-id-$dom_id", ['#type' => 'status_messages']));
         $request->query->set('ajax_page_state', $existing_page_state);
 
+        if (!empty($preview['#attached'])) {
+          $response->setAttachments($preview['#attached']);
+        }
+
         return $response;
       }
       else {