diff --git a/application/applicationextension.inc.php b/application/applicationextension.inc.php
index fb701ba2f..68da0a5d0 100644
--- a/application/applicationextension.inc.php
+++ b/application/applicationextension.inc.php
@@ -909,6 +909,8 @@ abstract class ApplicationPopupMenuItem
 /**
  * Class for adding an item into a popup menu that browses to the given URL
  *
+ * Note: This works only in the backoffice, {@see \URLButtonItem} for the end-user portal
+ *
  * @api
  * @package     Extensibility
  * @since 2.0
@@ -963,6 +965,8 @@ class URLPopupMenuItem extends ApplicationPopupMenuItem
 /**
  * Class for adding an item into a popup menu that triggers some Javascript code
  *
+ * Note: This works only in the backoffice, {@see \JSButtonItem} for the end-user portal
+ *
  * @api
  * @package     Extensibility
  * @since 2.0