diff --git a/htdocs/expensereport/class/expensereport.class.php b/htdocs/expensereport/class/expensereport.class.php
index 485373c5840..0b91f2c2699 100644
--- a/htdocs/expensereport/class/expensereport.class.php
+++ b/htdocs/expensereport/class/expensereport.class.php
@@ -46,6 +46,10 @@ class ExpenseReport extends CommonObject
 
     public $table_element_line = 'expensereport_det';
     public $fk_element = 'fk_expensereport';
+    
+    /**
+     * @var string String with name of icon for myobject. Must be the part after the 'object_' into object_myobject.png
+     */
     public $picto = 'trip';
 
     public $lines=array();