Swing JComboBox extension to remove unwanted border

I've spent the last few hours looking for a solution or even a decent guide to this problem, but I couldn't find anything.

I am implementing my own Swing Look and Feel for my little GUI. I've used the UIManager.put("key", values);

method so far with good success, but I'm stuck when it comes to modifying the JComboBoxes correctly.

Using this list, I was able to get my jComboBox closer to how I want them to look:

I have two problems with this, major and minor:

• Main

  

  I want the blue border shown to disappear.

• Minor

  

  I would really like the black border shown to disappear.

Apparently, no one key

in UIDefaults

has nothing to do with two boundaries: they seem to be some hard-coded in the variable model Look and Feel (which should be Metal). I resorted to manually extending ComboBoxRenderer and managed to come up with this:

package exec.laf.theme;

import java.awt.*;
import javax.swing.*;
import javax.swing.plaf.basic.BasicComboBoxRenderer;


public class ComboBoxRenderer extends BasicComboBoxRenderer {
    private Color background;
    private Color selectionBackground;

    public ComboBoxRenderer() {
        super();

        background = UIManager.getColor("ComboBox.background");
        selectionBackground = UIManager.getColor("ComboBox.selectionBackground");
    }

    public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
        setText((String) value);

        if (isSelected) setBackground(selectionBackground);
        else setBackground(background);

        return this;
    }
}

      

        
        
        
      

    

Where do I specify this renderer every time I create a JComboBox like this:

aComboBox.setRenderer(new ComboBoxRenderer());

      

        
        
        
      

    

get the same look and feel as the extended JComboBox.

The problem is, with this extension, I can't seem to find a way to touch those boundaries. Adding setBorder(new EmptyBorder(0, 0, 0, 0));

does nothing, as it just adds a border to the listed items.

I checked the source code javax.swing.plaf.basic.BasicComboBoxRenderer

to see if any borders were applied but nothing was found (the only border is the border applied to the listed elements, which I can override as shown above.

What I should do? Am I extending the wrong class, or am I missing something else?