Hi Everyone! I have a problem with openerp 7, i need add a message.subtype in stock.picking.in but every time, when i suscribe, automatically unsuscribe alone. Its like dont take the changes when i click on the message subtype, here the code

class stock_picking_in(osv.osv):
    _name = "stock.picking.in"
    _inherit = ['stock.picking.in','mail.thread']
    _track = {        
        'state':{            
            'stock.picking.subtype_xml': lambda self, cr, uid, obj, ctx=None: obj['state'] == 'done',            
            'stock.picking.subtype_xml2': lambda self, cr, uid, obj, ctx=None: obj['state'] != 'done',        
        }    
    }


stock_picking_in()