// assumes frame is supposed to be visible right now
svoid waitForFrameClose(JFrame f) {
  new Flag flag;
  new CloseablesHolder closer;
  
  swing {
    if (!isShowing(f))
      flag.raise();
    else
      closer.add(tempOnFrameClose(f, flag));
  }
  
  temp closer;
  flag.waitUntilUp();
}