UIDefaults defaults = UIManager.getLookAndFeelDefaults();  desktop.setBackground(defaults.getColor("desktop"));
Color bg = desktop.getBackground(); if (bg == null || bg instanceof UIResource) desktop.setBackground(UIManager.getColor("desktop"));
  protected void installDefaults()  {    UIDefaults defaults = UIManager.getLookAndFeelDefaults();    desktop.setBackground(defaults.getColor("desktop"));  }