public void updateActionState(ActionEvent evt) {
      super.updateActionState(evt);

      if (containsArg("format")) {
        f.setSelectedItem((String) getArg("format"));
      }
    }
 public void getArgsFromSource(Button but, ActionEvent evt) {
   super.getArgsFromSource(but, evt);
   putArg("format", (String) f.getSelectedItem());
 }