tree views must provide current variable names in context to start window actions

[Ferdinand]

the window action can be started from form view but not from tree view if a variable is to be placed in the context

Example
res.company
context
{'share_owner_id' : partner_id}

starting the action from tree view after selecting a company raises an error
Client Traceback (most recent call last):
  File "/home/gass/OpenERP/6.1/server/openerp/addons/web/common/http.py", line 180, in dispatch
    response["result"] = method(controller, self, **self.params)
  File "/home/gass/OpenERP/6.1/server/openerp/addons/web/controllers/main.py", line 1547, in load
    value = clean_action(req, action[0], do_not_eval)
  File "/home/gass/OpenERP/6.1/server/openerp/addons/web/controllers/main.py", line 687, in clean_action
    action['context'] = eval( action['context'], eval_ctx ) or {}
  File "<string>", line 1, in <module>
NameError: name 'partner_id' is not defined

after switching to form view the window action works fine