MAGETWO-96757: Fixed incorrect displaying of the sales rule conditions

Author: roman

app/code/Magento/SalesRule/Controller/Adminhtml/Promo/Quote/NewConditionHtml.php

@@ -1,12 +1,16 @@
 <?php
 /**
- *
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
 namespace Magento\SalesRule\Controller\Adminhtml\Promo\Quote;
 
-class NewConditionHtml extends \Magento\SalesRule\Controller\Adminhtml\Promo\Quote
+use Magento\Framework\App\Action\HttpPostActionInterface;
+
+/**
+ * Controller class NewConditionHtml. Returns condition html
+ */
+class NewConditionHtml extends \Magento\SalesRule\Controller\Adminhtml\Promo\Quote implements HttpPostActionInterface
 {
     /**
      * New condition html action
@@ -44,4 +48,4 @@ public function execute()
         }
         $this->getResponse()->setBody($html);
     }
-}
+}