title: Add a file under a file in Solution Explorer
body: <p>So in some cases, like when building WPF windows/user-controls and what not certain file types like <code>.xaml</code> and <code>.cs</code> get combined into "one" file (the <code>.cs</code> file is placed underneath the <code>.xaml</code>). </p>
  
  <p>The problem is that I know this guy that accidentally unbound the two files from each other, and I'm wondering if there is a way to help him put them back together again (or if there is a way to join files like this in general).</p>