def _on_value_changed_cb(self, spinbtn, prop):
        if not self.source:
            return

        value = spinbtn.get_value()

        res, cvalue = self.__get_source_property(prop)
        if not res:
            return

        if value != cvalue:
            self.__set_prop(prop, value)
            self.app.gui.editor.viewer.overlay_stack.update(self.source)