Submenu in JCombo

The JComboBox has a add(PopUpMenu) and a add(JMenuItem).

My class extends JComboBox. I create a JPopUpMenu, but it fails to display when I click on the JComboBox. Instead, nothing is displayed. Any ideas?

    JPopupMenu Pmenu = new JPopupMenu();
    JMenu textAndDataMenu = new JMenu("Text and Data");

    HashMap textAndData = new HashMap();

    public ComboMenu()
    {
        super();
        setUpTextAndData();
        add(Pmenu);  //----------this is where I add the menu

    }

    public void setUpTextAndData()
    {
        textAndData.put("Basic Text Box", TextBox.class);
        textAndData.put("Clear Text Box", ClearTextBox.class);
        textAndData.put("Table", Table.class);
        textAndData.put("Interactive Table", Intera开发者_开发知识库ctiveTable.class);
        textAndData.put("Graph", Graph.class);

        Set textAndDataKeys = textAndData.keySet();
        JMenuItem newMenuItem;
        for(String currKey : textAndDataKeys)
        {
            newMenuItem = new JMenuItem(currKey);
            newMenuItem.addActionListener(this);
            textAndDataMenu.add(newMenuItem);
        }

        Pmenu.add(textAndDataMenu);
    }

EDIT: Nevermind ... you know, I haven't messed with these in a while.

I think all you need to do is:

Pmenu.setInvoker(this);

before adding it in your constructor.