title: ContentThemeTransition on DataContext change
body: <p>In a Universal Windows Platform app a <strong>ContentThemeTransition</strong> can be applied to a ContentControl to <strong>animate the appearance of a new child control</strong>.</p>
  
  <p>Is there a way to get the same visual behavior (animation) when simply <strong>changing the DataContext on the existing child control</strong> (rather that creating a new child control instance each time, which seems wasteful)?</p>