Making a customable resizable JPanel, but it only works in certain L&F

Question

Hi,
I have created the following resizable JPanel (so that I can set a minimum size it can be dragged to).
However, I need it to work under the system L&F, which is XP, but it wont work.
The code is below. if you run it the first time, and try to resize the dialog to a small value, you will see it shrinks in size, to a certain point.
then if you comment out the 2 lines i specified, and run it again, it wont. Anyone have any ideas? is this a known bug?
import javax.swing.*;
import java.awt.event.ComponentListener;
import java.awt.event.ComponentEvent;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.*;
public class ResizeTest extends JDialog {
     public ResizeTest(JFrame owner) {
          super(owner);
          this.addComponentListener(resizeListener);
          /* comment out the following 2 lines */
          setUndecorated(true);                  
        getRootPane().setWindowDecorationStyle(JRootPane.PLAIN_DIALOG);
     private ComponentListener resizeListener = new ComponentListener() {
          public void componentHidden( ComponentEvent i_e ) { }
          public void componentMoved( ComponentEvent i_e ) { }
          public void componentResized( ComponentEvent i_e ) {
               int width = ResizeTest.this.getWidth();
               int height = ResizeTest.this.getHeight();   
              if( width < 50 ) { width = 50; }
               if( height < 50 ) { height = 50; }
               ResizeTest.this.setSize( width, height );
         public void componentShown( ComponentEvent i_e ) { }
     private static void test() {
          final JFrame frame = new JFrame();
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          JButton launchButton = new JButton("showDialog");
          frame.setContentPane(launchButton);
          final ResizeTest testDialog = new ResizeTest(frame);
          testDialog.setMinimumSize(new Dimension(300, 300));
          testDialog.setSize(500, 500);
          testDialog.setPreferredSize(new Dimension(500, 500));
          launchButton.addActionListener(new ActionListener() {
               public void actionPerformed(ActionEvent e) {
                    testDialog.pack();
                    testDialog.setVisible(true);
          SwingUtilities.invokeLater(new Runnable() {
               public void run() {
                    frame.pack();
                    frame.setVisible(true);
     public static void main(String[] args) {
          test();
}

Answer 1

okay... I see what the problem is.
1) With those lines uncommented: The L&F is handling the window decorations. Because of this, it's basically a JWindow with custom painting and mouse handling. When you resize, it's constantly calling setSize, which constantly firing events, so your minimum sizing works as you expect.
2) With those lines commented: The OS is handling the window decorations. Because of this, there are 2 caveats:
a) There is a minimum width of the window of what looks like about 120-130 pixels. So you can't go any smaller then that for width. And for height, no smaller then the titlebar and lower border.
b) It only fires the component events when the mouse is released, cuz that's how the undelying native windows deal with it... or at least with Java.
For #1 above, there's still a minimum size for the L&F decorated windows. But this is related to what content is showing in the titlebar. Which in the case of the decorations showing, is smaller then what your were defining as a minimum.
So, basically, it's not a bug. It's just the way it is. It's always been like this.