if (comboBox.getForeground() instanceof UIResource)
if (fore == null || fore instanceof UIResource)
  protected void installDefaults()  {    UIDefaults defaults = UIManager.getLookAndFeelDefaults();    if (comboBox.getFont() instanceof UIResource)      comboBox.setFont(defaults.getFont("ComboBox.font"));        if (comboBox.getForeground() instanceof UIResource)      comboBox.setForeground(defaults.getColor("ComboBox.foreground"));    if (comboBox.getBackground() instanceof UIResource)      comboBox.setBackground(defaults.getColor("ComboBox.background"));    // fetch the button color scheme    shadow = defaults.getColor("ComboBox.buttonShadow");    darkShadow = defaults.getColor("ComboBox.buttonDarkShadow");    highlight = defaults.getColor("ComboBox.buttonHighlight");  }