title: Xamarin.Forms Disable slide menu in pushed page
body: <p>I use Xamarin.Forms (ver 1.4)</p>
  <p>Page hierarchy:</p>
  <blockquote>
  <p>-&gt;NavigationPage</p>
  <p>--&gt;MasterDetailPage</p>
  </blockquote>
  <p>How can disable sliding menu (open master page by gesture) in pushed screen?</p>
  <p>Push method:</p>
  <blockquote>
  <p>await ((NavigationPage)((MasterDetailPage)Application.Current.MainPage).Detail).PushAsync(page))</p>
  </blockquote>
  <p>Sliding menu should work only on root page.</p>