Trying to get JComboBox to "repopulate" with increased java.util.Vector

I have a JFrame with two JPanels

Top JPanel p1 contains:

1 JLabel that never changes
1 JComboBox that is populated by dynamic values found in
java.util.Vector
1 JButton

If you press that JButton this method fires off:

[code]
/**
     * Process new {@link java.net.URL} request
     */
    protected void processURL() {
        System.out.println("Your new URL is " +
webAddressBox.getSelectedItem().toString()); // webAddress is
JComboBox
        SimpleBrowser.hasEnteredAdditionalURL = true;
        setURLPath(webAddressBox.getSelectedItem().toString()); //
WORKS
        try {
            addToHistoryURLVector(new
URL(webAddressBox.getSelectedItem().toString())); // WORKS
        } catch (Exception e) {}
        generateWebBrowser(); // WORKS - CREATES
org.jdesktop.jdic.browser.WebBrowser each time you enter in a URL in
JComboBox and press JButton
        webAddressBox = null;
        generateJComboBox(); // THIS SHOULD CREATE A BRAND NEW
REPOPULATED JComboBox
        p1.revalidate();
    }

/**
     * Populate {@link #webAddressBox} optionally using {@link
#historyURLVector}
     */
    private void generateJComboBox() {
        if (historyURLVector != null && historyURLVector.size() > 0) {
            webAddressBox = new JComboBox(historyURLVector);
        } else {
            webAddressBox = new JComboBox();
        }
        if (!SimpleBrowser.hasAddedInitialURL && getURL() != null) {
            webAddressBox.addItem(getURL());
        } else if (!SimpleBrowser.hasAddedInitialURL && getURLPath() !
= null) {
            webAddressBox.addItem(getURLPath());
        }
        if (getScreenWidth() == 0)
setScreenWidth(SimpleBrowser.DEFAULT_SCREEN_WIDTH);
        Dimension dim = new Dimension((int)(getScreenWidth() / 1.14),
                (int)(SimpleBrowser.DEFAULT_WEB_ADDRESS_BAR_HEIGHT /
2));
        webAddressBox.setMaximumSize(dim);
        webAddressBox.setPreferredSize(dim);
        webAddressBox.setEditable(true);
        webAddressBox.setBackground(Color.WHITE);
    }
[/code]

When the JFrame fires up the first time, I see my top JPanel just
right with just one value in it, and the bottom JPanel with the URL
displayed. I enter another URL into the JComboBox and click the
JButton; while the bottom JPanel refreshes with a brand new URL
displayed, the top one shows ONLY the new URL; I want to display a
total dropdown of ALL URLS you have ever entered from the first until
now as a "historyURLVector" so to speak. The values in
java.util.Vector accurately reflect that you have now 2 URLS for
example instead of just the initial 1 URL, but the JCombBox only shows
1 URL when you want to see all of them.

Best way to understand this would be very easy: just like your address
bar in your browser should show multiple URLs, so should mine, but I
can't figure out how to do this part of it all the while having a semi-
working simple browser.

Thanx
Phil