def update_event(self, hint, obj):
        """Updates tree colums when itemdata is changed."""

        tree = self.treeview
        data = obj
        item = self.get_item_by_data(obj)
        if item:
            if data.get_id() != tree.item(item, 'text'):
                tree.item(item, text=data.get_id())
            # if tree.parent(item) != '' and 'layout' in data:
            if tree.parent(item) != '':
                row = data.get_layout_property('row')
                col = data.get_layout_property('column')
                values = tree.item(item, 'values')
                if (row != values[1] or col != values[2]):
                    values = (data.get_class(), row, col)
                tree.item(item, values=values)
            self.draw_widget(item)
            self.app.set_changed()
Updates tree colums when itemdata is changed.