ModalDialog and returning back

[Alex]

Dear All,
I have an application that on renderOnDomReadyJavascript shows Modal Dialog
for 5 seconds and then closes it. It is kind of Logo. Unfortunately if user
goes to another site and returns back then “Page expired” is displayed in
this Modal Dialog and it is not closes. Is it possible to avoid showing
this Modal Dialog after user returns to my application pressing “Back”
Button on the Browser or to show it properly for 5 sec.
Thanks a lot in advance,
Alex

public class LogoStarter {
    private static final Logger log =
LoggerFactory.getLogger(LogoStarter.class);

    public LogoStarter(final WebPage webPage) {
        final ModalWindow modalLogo;
        final ModalWindow modalInfo;

        webPage.add(modalLogo = new OpenOnLoadModalWindow("modalLogo"));
        modalLogo.setTitle("");
        modalLogo.setPageCreator(new ModalWindow.PageCreator() {
            private static final long serialVersionUID =
2674999186672458996L;
            public Page createPage() {
                return new Logo();
            }
        });

        webPage.add(new AjaxLink<Object>("logo") {
                    public void onClick(AjaxRequestTarget target) {
                        if (target != null) {
                            modalLogo.show(target);
                        } else {
                            System.out.println("JS off");
                            setResponsePage(new Logo(JS_OFF_MSG));
                        }

                    }
                });

        webPage.add(new AbstractAjaxTimerBehavior(Duration.seconds(5)) {
            protected void onTimer(AjaxRequestTarget target) {
                if (modalLogo.isShown())
                    modalLogo.close(target);
                stop();
            }
        });
    }
}

public class OpenOnLoadModalWindow extends ModalWindow implements
IHeaderContributor {

    public OpenOnLoadModalWindow(String id) {
            super(id);
    }

    public OpenOnLoadModalWindow(String id, IModel<?> model) {
            super(id, model);
    }

    public void renderHead(IHeaderResponse response)
    {
           response.renderOnDomReadyJavascript(getWindowOpenJavascript());
    }

   protected boolean makeContentVisible()
    {
            return true;
    }
}