diff --git a/core/misc/ajax.js b/core/misc/ajax.js
index b2eb6fb..0ccd579 100644
--- a/core/misc/ajax.js
+++ b/core/misc/ajax.js
@@ -272,7 +272,7 @@
       else {
         ajax.options.url += '&';
       }
-      ajax.options.url += '_wrapper_format=' + element_settings.dialogType;
+      ajax.options.url += '_wrapper_format=drupal_' + element_settings.dialogType;
     }
 
     // Bind the ajaxSubmit function to the element event.