Always display tree views to keep model up to date

Any tree view may be used even if it is not shown e.g. to save tree state. So
the model of TreeView which keeps a reference to the group must be updated if
the group has changed.

issue7885
review60491002

tryton/gui/window/view_form/screen/screen.py

@@ -905,7 +905,11 @@ class Screen(SignalEvent):
             self.search_active(self.current_view.view_type
                 in ('tree', 'graph', 'calendar'))
             for view in self.views:
+                # Always display tree view to update model
+                # because view can be used even if it is not shown
+                # like for save_tree_state
                 if (view == self.current_view
+                        or view.view_type == 'tree'
                         or view.widget.get_parent()):
                     view.display()
             self.current_view.widget.set_sensitive(