title: Why does Visual Studio create a new .vsmdi file?
body: <p>If I open a solution in Visual Studio 2008 and run a unit test then VS creates a new .vsmdi file in the Solution Items folder and gives it the next number available e.g. My Solution2.vsmdi.</p>
  
  <p>Any idea why VS is doing this and how I can get it to stop doing this?</p>