JTextField doesn't get focus or loses focus forever

FULL PRODUCT VERSION :
java version "1.7.0_03"
Java(TM) SE Runtime Environment (build 1.7.0_03-b04)
Java HotSpot(TM) Client VM (build 22.1-b02, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Linux Celsius 3.2.6 #1 SMP Wed Feb 15 12:04:35 CET 2012 i686 Intel(R) Pentium(R) D CPU 3.20GHz GenuineIntel GNU/Linux

EXTRA RELEVANT SYSTEM CONFIGURATION :
XWindow manager: IceWM. No KDE, Gnome or such.

A DESCRIPTION OF THE PROBLEM :
1. A JTextField created as a child of the main JFrame _never_ gets the focus when the user clicks into it.

2. A JTextField in a dynamically created JDialog loses the focus as soon as the cursor is moved out of the parent JFrame, and _never_ gets it back.

No such problems on Windows XP!

REGRESSION. Last worked in version 6u29

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Start attached test program.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Text field should gain focus when clicked into.
ACTUAL -
Text field gets focus once and then loses it forever, or doesn't get it at all.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

// Focus bug

public class Focusbug
    extends JFrame
{
    JDialog dia;

    Focusbug(String titel)
    {
        super(titel);
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        dia = new JDialog(this);
        dia.setBounds(10, 10, 200,70);
        dia.add(new JTextField("One-way focus"));

        JButton start = new JButton("Create dialog");

        start.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                dia.setVisible(true);
            }
        });

        add(start, BorderLayout.NORTH);

        JPanel panel = new JPanel();

        panel.add(new JTextField("No focus here"));
        add(panel, BorderLayout.SOUTH);
    }
    
    static public void main(String[] args)
    {
        Focusbug focusbug = new Focusbug("Focusbug");

        focusbug.setBounds(100, 100, 250, 100);
        focusbug.setVisible(true);
    }
}


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