diff --git a/htdocs/core/class/html.formticket.class.php b/htdocs/core/class/html.formticket.class.php
index cba880dfada..91fad1dba09 100644
--- a/htdocs/core/class/html.formticket.class.php
+++ b/htdocs/core/class/html.formticket.class.php
@@ -47,6 +47,9 @@ class FormTicket
 	 */
 	public $db;
 
+	/**
+	 * @var string	The track_id of the ticket. Used also for the $keytoavoidconflict to name session vars to upload files.
+	 */
 	public $track_id;
 
 	/**