diff --git a/templates/sidebar.block.recent.php b/templates/sidebar.block.recent.php
index cc04b97..a128e70 100644
--- a/templates/sidebar.block.recent.php
+++ b/templates/sidebar.block.recent.php
@@ -3,7 +3,7 @@ $b2tservice =& ServiceFactory::getServiceInstance('Bookmark2TagService');
 $userservice =& ServiceFactory::getServiceInstance('UserService');
 
 /* Manage input */
-$userid = isset($userid)?$userid:0;
+$userid = isset($userid)?$userid:NULL;
 
 $logged_on_userid = $userservice->getCurrentUserId();
 if ($logged_on_userid === false) {