Missing on_change on party

opportunity.py

@@ -35,7 +35,7 @@ class SaleOpportunity(Workflow, ModelSQL, ModelView):
     _rec_name = 'description'
 
     party = fields.Many2One('party.party', 'Party', required=True, select=True,
-            states=_STATES_STOP, depends=_DEPENDS_STOP)
+        on_change=['party'], states=_STATES_STOP, depends=_DEPENDS_STOP)
     address = fields.Many2One('party.address', 'Address',
         domain=[('party', '=', Eval('party'))],
         select=True, depends=['party', 'state'],