diff --git a/plugins/calendar/calendar.php b/plugins/calendar/calendar.php
index 3b7e76f6..f4aeaa19 100644
--- a/plugins/calendar/calendar.php
+++ b/plugins/calendar/calendar.php
@@ -499,7 +499,7 @@ class calendar extends rcube_plugin
       }
 
       $p['blocks']['view']['options']['alarmtype'] = array(
-        'title' => html::label($field_id, Q($this->gettext('defaultalarmtype'))),
+        'title' => html::label($field_id, rcube::Q($this->gettext('defaultalarmtype'))),
         'content' => $alarm_type . ' ' . $alarm_offset,
       );
     }