In the tree view nothing happens if you click for instance on the new button or on records
this is the action:
    def res_partner_action_search_task(self):

        return {            "type": "ir.actions.act_window", 

           "name": "Look for a task",  

          "res_model": "project.task",     

       "view_mode": "tree",     

       "view_id": self.env.ref(                       

 "project.open_view_all_tasks_list_view"                   

 ).id,