shell.setLocation(ploc.x + (psize.x - size.x) / 2, ploc.y + (psize.y - size.y) / 2);
  public void showURL(URL url) {    if (shell == null) {      createShell();      createText(url);      createCloseButton();      shell.pack();      Point size = shell.getSize();      Point ploc = parent.getLocation();      Point psize = parent.getSize();      shell.setLocation(ploc.x + (psize.x - size.x) / 2, ploc.y + (psize.y - size.y) / 2);        // Open the window and process the events.      shell.open();    }  }