Java SE (Java Platform, Standard Edition)

Hello,

the following code shows a JCheckBox which changes its background colour when selected, thus serving as an eye catcher in a frame with several columns of checkboxes.
The only thing I would like to improve is that the ceckbox should keep the normal ocean LAF when unselected. Even when I comment out the special colouring and just do a super.paintIcon(...), it remains flat gray. Any ideas why?

import java.awt.*;  
import java.awt.event.*;  
import javax.swing.*;

public class HighlightedCheckBox extends JFrame {
  JCheckBox cbx;

  public HighlightedCheckBox() {
    setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    setSize(300,200);
    setLayout(new FlowLayout(FlowLayout.LEFT, 40, 40));
    cbx= new JCheckBox("The modified checkbox");
    HighlightOnSelectIcon icon= new HighlightOnSelectIcon(cbx);
    cbx.setIcon(icon);
    JCheckBox cb= new JCheckBox("Above checkbox enabled", true);
    cb.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
	cbx.setEnabled(!cbx.isEnabled());
      }
    });
    add(cbx);
    add(cb, BorderLayout.SOUTH);
    setVisible(true);
  }


  public static void main(String args[]) {
    EventQueue.invokeLater(new Runnable() {
      public void run() {
	new HighlightedCheckBox();
      }
    });
  }


  class HighlightOnSelectIcon extends javax.swing.plaf.metal.MetalCheckBoxIcon {
    JCheckBox cb;

    public HighlightOnSelectIcon(JCheckBox cb) {
      this.cb= cb;
    }

    protected void drawCheck(Component c, Graphics g, int x, int y) {
      g.setColor(Color.BLACK);
      super.drawCheck(c,g,x,y);
    }

    public void paintIcon(Component c, Graphics g, int x, int y) {
//      if (cb.isSelected()) g.setColor(Color.GREEN);
//      g.fillRect(x,y,getIconWidth()-3,getIconHeight()-1);
      super.paintIcon(c,g,x,y);
    }
  }

}