diff --git a/product/ERP5/PropertySheet/CalendarConstraint.py b/product/ERP5/PropertySheet/CalendarConstraint.py
index 63ce76e2d58425bfc482f8d3f58f09147adeadd7..502db7d91bc2f54d0691c7ac1572afc6eedc8040 100644
--- a/product/ERP5/PropertySheet/CalendarConstraint.py
+++ b/product/ERP5/PropertySheet/CalendarConstraint.py
@@ -33,24 +33,24 @@ class CalendarConstraint:
 
   _constraints = (
     { 'id'            : 'presence_request_line',
-      'description'   : 'Must contain at least one period',
       'type'          : 'ContentExistence',
       'portal_type'   : ('Presence Request Period', ),
       'description'   : 'No Presence Request Period created yet',
+      'message_no_subobject_portal_type': 'No Presence Request Period created yet',
       'condition' :   'python: object.getPortalType() == "Presence Request"',
     },
     { 'id'            : 'leave_request_line',
-      'description'   : 'Must contain at least one period',
       'type'          : 'ContentExistence',
       'portal_type'   : ('Leave Request Period', ),
       'description'   : 'No Leave Request Period created yet',
+      'message_no_subobject_portal_type': 'No Leave Request Period created yet',
       'condition' :   'python: object.getPortalType() == "Leave Request"',
     },
     { 'id'            : 'group_request_line',
-      'description'   : 'Must contain at least one period',
       'type'          : 'ContentExistence',
       'portal_type'   : ('Group Leave Period', 'Group Presence Period', ),
       'description'   : 'No Calendar Line created yet',
+      'message_no_subobject_portal_type': 'No Calendar Line created yet',
       'condition' :   'python: object.getPortalType() == "Group Calendar"',
     },