private boolean isInternalFrameSystemMenu(){
    String actionCommand=menuItem.getActionCommand();
    if(
      ("Close".equals(actionCommand))||
      ("Minimize".equals(actionCommand))||
      ("Restore".equals(actionCommand))||
      ("Maximize".equals(actionCommand))
    ){
      return true;
    } else{
      return false;
    }
  }
private boolean isInternalFrameSystemMenu()