[6.1/trunk] location structure bug: KeyError: 'active_id'

this is using rev #1396

go to warehouse> inventory control> location structure
then select some location in the tree view and double click on it to browse its product list, you will ge this stack trace:

Client Traceback (most recent call last):
  File "/opt/openerp/prod/addons/web/common/http.py", line 154, in dispatch
    response["result"] = method(controller, self, **self.params)
  File "/opt/openerp/prod/addons/web/controllers/main.py", line 724, in call_button
    action = self.call_common(req, model, method, args, domain_id, context_id)
  File "/opt/openerp/prod/addons/web/controllers/main.py", line 716, in call_common
    return getattr(req.session.model(model), method)(*args)
  File "/opt/openerp/prod/addons/web/common/openerplib/main.py", line 417, in proxy
    *args)
  File "/opt/openerp/prod/addons/web/common/openerplib/main.py", line 294, in proxy
    result = self.connector.send(self.service_name, method, *args)
  File "/opt/openerp/prod/addons/web/common/openerplib/main.py", line 264, in send
    raise fault

Server Traceback (most recent call last):
  File "/opt/openerp/prod/addons/web/common/openerplib/main.py", line 245, in send
    result = openerp.netsvc.dispatch_rpc(service_name, method, args)
  File "/opt/openerp/prod/server/openerp/netsvc.py", line 325, in dispatch_rpc
    result = ExportService.getService(service_name).dispatch(method, params)
  File "/opt/openerp/prod/server/openerp/service/web_services.py", line 580, in dispatch
    res = fn(db, uid, *params)
  File "/opt/openerp/prod/server/openerp/osv/osv.py", line 120, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/opt/openerp/prod/server/openerp/osv/osv.py", line 172, in execute
    res = self.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/opt/openerp/prod/server/openerp/osv/osv.py", line 163, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/opt/openerp/prod/addons/stock/wizard/stock_location_product.py", line 49, in action_open_window
    'context': {'location': context['active_id'],
KeyError: 'active_id'