!7

cmodule NestedDesktopPane {
  transient JDesktopPane desktopPane;
  L<Win> windows = syncL();

  sclass Win {
    Rect rect;
    S title;
    transient JInternalFrame frame;

    !include #1027843 // setField
  }

  visualize {
    desktopPane = jDesktopPane();
    restoreFrames();
    ret withCenteredButtons(desktopPane,
      "Add frame", rThreadEnter addAFrame);
  }

  void unvisualize {
    super.unvisualize();
    for (Win win : windows) win.frame = null;
  }
  
  void addAFrame {
    JInternalFrame f = showInternalFrame(desktopPane, "Hello world");
    new Win win;
    win.rect = boundsAsRect(f);
    win.title = internalFrameTitle(f);
    win.frame = f;
    windows.add(win);
    onBoundsChange(f, r { grabRect(win) });
    change();
  }

  void restoreFrames {
    for (Win win : windows)
      win.frame = setBounds(win.rect, showInternalFrame(desktopPane, win.title));
  }

  void grabRect(Win win) {
    if (win != null && win.frame != null && set_trueIfChanged(win, rect := boundsAsRect(win.frame)))
      change();
  }
}