FULL PRODUCT VERSION :
java version "1.5.0_09"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_09-b03)
Java HotSpot(TM) Client VM (build 1.5.0_09-b03, mixed mode, sharing)

java version "1.6.0"
Java(TM) SE Runtime Environment (build 1.6.0-b105)
Java HotSpot(TM) Client VM (build 1.6.0-b105, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]
Microsoft Windows 2000 [Version 5.00.2195]

A DESCRIPTION OF THE PROBLEM :
If a JFrame contains an AWT Canvas, the size of the JFrame can only be enlarged but not reduced when JFrame.setDefaultLookAndFeelDecordated(true) is used.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Simply run the test case or...
1. Set JFrame.setDefaultLookAndFeelDecorated(true);
2. Set the UIManager to use any look and feel that can draw its own frame decorations, such as Metal.
3. Create a JFrame
4. Create a JPanel with BorderLayout or GridLayout and set it as the content pane for the JFrame
5. Create a Canvas and add it to the JPanel.
6. Start program and show the JFrame.
7. Try to reduce the size of the JFrame.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
JFrame should be able to get larger or smaller in either the horizontal or vertical direction.
ACTUAL -
JFrame will get larger in either direction, but will not get smaller in any direction.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
No error messages.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.awt.BorderLayout;
import java.awt.Canvas;

import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.plaf.metal.MetalLookAndFeel;


public class TestLookAndFeelError extends JFrame {
    public TestLookAndFeelError() {
        try {
            JPanel mainPanel = new JPanel(new BorderLayout());
            mainPanel.add(new Canvas(), BorderLayout.CENTER);
            setContentPane(mainPanel);
            setSize(400, 300);
        }
        catch(Exception e) {
            e.printStackTrace();
        }
    }
    public static void main(String args[]) {
        System.out.println(System.getProperty("java.vm.version"));
        try {
            JFrame.setDefaultLookAndFeelDecorated(true);
            UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        TestLookAndFeelError t = new TestLookAndFeelError();
        t.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        t.setVisible(true);
    }
}


---------- END SOURCE ----------