When I'm setting up a connection with Facebook: New Message as my event, but decide to cancel it (using the Cancel button inside the config window's display of the FB page, rather than the config window's own Cancel button), Mayhem crashes, giving me this error:

ArgumentNullException was unhandled by user code
Value cannot be null.
Parameter name: accessToken

private void LoadUser()

    {
        var fb = new FacebookClient(TokenProp);    ///ERRONEOUS LINE OF CODE

        dynamic result = fb.Get("/me");
        var uId = result.id;
        User_Info.Text = result.name;

        BitmapImage bi = new BitmapImage();
        bi.BeginInit();
        bi.UriSource = new Uri(String.Format("http://graph.facebook.com/{0}/picture", uId), UriKind.Absolute);
        bi.EndInit();

        Profile.Source = bi;

        // for login success
        CanSave = true;
        Revalidate();
        // remove after debug
        webBrowser.Navigate("www.facebook.com");
    }