Hmmm....just wrote a little test up and in there it works...what the heck
could that be? I'm using a JFrame with JInternalFrames and a GlassPane to
simulate modal dialogs.

Here's the test app that shows the correct behaviour...maybe someone has an
ideas of how to modify it to make it NOT work so I can track down the bug.

import javax.swing.*;
import java.awt.*;

public class Test extends JFrame
{
public Test()
{
 super("Test");
 setSize(500, 400);
 setVisible(true);
 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

 Object[] items = new Object[100];
 for(int i = 0; i < items.length; ++i)
 {
  items[i] = new String("Eintrag " + i);
 }

 setLayout(null);
 JComboBox comboBox = new JComboBox(items);
 comboBox.setLightWeightPopupEnabled(false);
 comboBox.setSize(320, 20);
 comboBox.setLocation(30, 30);
 getContentPane().add(comboBox);

 repaint();
}

public static void main(String arguments[])
{
 Test test = new Test();
}
}