JComboBox will not open inside of JTabbedPane

Question

I have a problem with comboboxes which are inside of tabbedpanes. They will not pop open to select other items stored in the model.
I tried 1.5.0.10 and 1.5.0.11 so far. Problem is the same.
Any Ideas ? Anybody ?
I cut it down to the following code:
import java.awt.BorderLayout;
import javax.swing.JComboBox;
import javax.swing.JPanel;
import javax.swing.JTabbedPane;
public class TestTabbedPane extends JPanel {
     JTabbedPane _pane;
     public TestTabbedPane() {
          super();
          setLayout(new BorderLayout());
          _pane = new JTabbedPane();
          for (int i = 0; i < 10; i++) {
               _pane.addTab("Tab "+i, new TestComponent());
          add(_pane, BorderLayout.CENTER);
     class TestComponent extends JPanel {
          JComboBox _combo;
          public TestComponent() {
               super();
               _combo = new JComboBox(new String[]{"1", "2", "3"});
               this.add(_combo);
     public static void main(String[] args){
          TestTabbedPane ttp = new TestTabbedPane();
          QnDFrame frame = new QnDFrame(ttp);
          frame.setVisible(true);
import java.awt.BorderLayout;
import javax.swing.JComponent;
import javax.swing.JFrame;
/** Quick and Dirty Frame  */
public class QnDFrame extends JFrame {
     public QnDFrame(JComponent comp) {
          super(comp.getClass().getName());
          this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          this.setSize(1024, 768);
          this.getRootPane().setLayout(new BorderLayout());
          this.getRootPane().add(comp, BorderLayout.CENTER);
          this.pack();
}

Answer 1

// this.getRootPane().setLayout(new BorderLayout());
//this.getRootPane().add(comp, BorderLayout.CENTER);
this.getContentPane().add(comp, BorderLayout.CENTER);