docs: def on_add(self, widget, data=None):
          """Create a new scoped variable with default values"""
          if isinstance(self.model, ContainerStateModel):
              try:
                  scoped_var_ids = gui_helper_state_machine.add_scoped_variable_to_selected_states(selected_states=[self.model])
                  if scoped_var_ids:
                      self.select_entry(scoped_var_ids[self.model.state])
              except ValueError as e:
                  logger.warning("The scoped variable couldn't be added: {0}".format(e))
                  return False
  
              return True