How do you rebuild the GWT History stack?

I have a larger application that I'm working with but the GWT History documentation has a simple example that demonstrates the problem. The example is copied for convenience:

public class HistoryTest implements EntryPoint, ValueChangeHandler
{
    private Label lbl = new Label();

    public void onModuleLoad()
    {
        Hyperlink link0 = new Hyperlink("link to foo", "foo");
        Hyperlink link1 = new Hyperlink("link to bar", "bar");
        Hyperlink link2 = new Hyperlink("link to baz", "baz");

        String initToken = History.getToken();

        if (initToken.length() == 0)
        {
            History.newItem("baz");
        }

        // Add widgets to the root panel.
        VerticalPanel panel = new VerticalPanel();
        panel.add(lbl);
        panel.add(link0);
        panel.add(link1);
        panel.add(link2);
        RootPanel.get().add(panel);

        History.addValueChangeHandler(this);        // Add history listener
        History.fireCurrentHistoryState();
    }

    @Override
    public void onValueChange(ValueChangeEvent event)
    {
        lbl.setText("The current history token is: " + event.getValue());
    }
}

The problem is that if you refresh the application, the history stack gets blown away. How do you preserve the history so that if the user refreshes the page, the back button is still useful?

I have just tested it with Firefox and Chrome for my application and page refresh does not clear the history. Which browser do you use? Do you have the

<iframe src="javascript:''" id='__gwt_historyFrame' style='position:absolute;width:0;height:0;border:0'></iframe>

in your HTML?