How to open a new tab using HyperlinkButton after answer on MessageBox?

See more:

Silverlight

MessageBox

There was a following situation with an event handler

private void Bt_Click(object sender, RoutedEventArgs e)
{
    if (MessageBox.Show("Yes or No", "?", MessageBoxButton.OKCancel) != MessageBoxResult.OK)
    {
        return;
    }

    HyperlinkButton hb = new HyperlinkButton()
    {
        NavigateUri = new Uri(HtmlPage.Document.DocumentUri.OriginalString.Split('#')[0] + "#/ViewTask1", UriKind.Absolute),
        TargetName = "_blank"
    };
    (new HyperlinkButtonAutomationPeer(hb) as IInvokeProvider).Invoke();
}

After a long pause before pressing OK on MessageBox new tab does not appear. But if remove the question or quick answer Yes (pressing the space on the keyboard) opening tabs is successful.

Help Me, Please
How to open a new tab after answer Yes?