static void cleanExitOnFrameClose_ifStillInSameFrame(Component c) {
  cleanExitOnFrameClose_ifStillInSameFrame(c, null);
}

static void cleanExitOnFrameClose_ifStillInSameFrame(final Component c, IF0<Bool> confirm) {
  final Window w = getWindow(c);
  if (w == null) ret;
  onWindowClosing(w, r {
    if (getWindow(c) == w) thread {
      if (!isFalse(callF(confirm)))
        cleanKillVM();
    }
  });
}