if (b.getBackground() instanceof UIResource)
  protected void uninstallDefaults(AbstractButton b)  {    if (b.getFont() instanceof UIResource)      b.setFont(null);    b.setForeground(null);    b.setBackground(null);    if (b.getBorder() instanceof UIResource)    b.setBorder(null);    b.setIconTextGap(defaultTextIconGap);    if (b.getMargin() instanceof UIResource)    b.setMargin(null);  }