Issue with Java version 6u24

JMenuItem text will be reset to null if an generic action command is set for
buttons. It can be reproduced with following code.

Test case:
public class Start
{

    JTree tree = new JTree();

    public Start() {
        tree.setEditable(true);
        tree.addMouseListener(new GenericMouseAdapter());

        JFrame test = new JFrame();
        test.add(new JScrollPane(tree));
        test.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        test.setSize(500, 500);
        test.setLocationRelativeTo(null);
        test.setVisible(true);

    }

    private class GenericMouseAdapter extends MouseAdapter {

        @Override
        public void mousePressed(MouseEvent event) {

            if (SwingUtilities.isRightMouseButton(event)) {

                TreePath path = tree.getPathForLocation( event.getX(),
event.getY());
                if (path!=null) {
                    tree.setSelectionPath(path);

                    Action itemAction = new AbstractAction() {

                        @Override
                        public void actionPerformed(ActionEvent e) {
                            System.out.println("Do nothing");
                        }
                    };
                    JPopupMenu menu = new JPopupMenu();

                    // copy
                    JMenuItem copy = new JMenuItem("Button 1");
                    copy.setAction(itemAction);
                    menu.add(copy);

                    menu.add(new JPopupMenu.Separator());

                    // find
                    JMenuItem find = new JMenuItem("Button 2");
                    find.setAction(itemAction);
                    menu.add(find);

                    // show popup
                    menu.setVisible(true);
                    menu.show(event.getComponent(), event.getX(),
event.getY());
                }
            }
        }
    }

    public static void main(String[] args){
        new Start();
    }
}