Is it possible to have an Opaque Border

Question

Is it possible to have a transparent border? I'm asking because I'm putting a component into one of Hans Mullers wizzzy MultiSplitPanes which in turn is opaque because It's used inside a TabbedPane (XP colours these with a white background gradient .i.e. not dialog grey).
The tree with scrollpane weren't quite centered so a slapped an empty border on it with insets to make it look square, but the border - even empty ones appear opaque when used inside a transparent component?! Anyone seen this before?
nb.I'd guess it would be possible to nest the scrollpane inside yet another transparent panel with a gridbag insets of (2,2,3,2).. but that seems even more of a pain just to shuffle up one pixel.
This should illustrate the problem, you shouldnt see any grey around the tree:
import javax.swing.*;
import javax.swing.border.EmptyBorder;
import java.awt.*;
public class BorderShouldNotBeSeen {
    public static void main(String[] args) {
        JFrame frame = new JFrame();
        JPanel panel = new JPanel();
        frame.getContentPane().add(panel);
        // make it really obvious, should see red right up to the darker scrollpane/tree border
        frame.getContentPane().setBackground(Color.RED);
        panel.setOpaque(false);
        // just BorderFactory.createEmptyBorder() didnt cut it.. so then I used..
        class MyBorder extends EmptyBorder {
            public MyBorder(Insets insets) {
                super(insets);
            public boolean isBorderOpaque() {
                // ..guess what it still looks opaque!
                return false;
        JScrollPane treePane = new JScrollPane(new JTree());
        treePane.setBorder(BorderFactory.createCompoundBorder(
                new MyBorder(new Insets(10, 10, 11, 10)), treePane.getBorder()));
        panel.add(treePane);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
}- Richard

Answer 1

Wow, yes that fixes it - obvious when you think about it, the borders were just increasing the insets on the component. Just didn't see it.. Thanks.