title: The configSource file 'Unity.xml' is also used in a parent, this is not allowed
body: <p>I've got a VS 2013 c# (.NET 4.5) solution with 10 projects.<br>
  2 of them (the presentation one and a web service -WCF-) have similar config options:  </p>
  
  <ul>
  <li>Web.config with<br>
  <code>&lt;configSections&gt;
   &lt;section name="unity" type="Microsoft.Practices.Unity.Configuration.UnityConfigurationSection, Microsoft.Practices.Unity.Configuration" /&gt;
   &lt;/configSections&gt;</code><br>
  and<br>
  <code>&lt;unity configSource="Unity.xml" /&gt;</code></li>
  <li>And a Unity.xml with Unity configuration, identical in both projects.   </li>
  </ul>
  
  <p>When I start the solution (I've tried to start both projects or just the WS) the presentation project starts well but the WS is not able to add a service, triggering the message:<br>
  <code>The configSource file 'Unity.xml' is also used in a parent, this is not allowed.</code></p>
  
  <p>If I delete the <code>&lt;unity configSource="Unity.xml" /&gt;</code> line the services are added, but obviously the application doesn't work because I don't have the persistence access.</p>
  
  <p>Any idea? Can I share more relevant data?
  I'm deploying in IIS Express.</p>
  
  <p>BTW, the project worked some weeks ago. Something must have changed, but I've got no idea of what, because I've been working with other solutions meanwhile, not this.</p>
  
  <p>I'm a bit lost... As you can see :)</p>
  
  <p>Thanks!</p>
  
  <p><strong>Edit:</strong> I forgot to say that the same project downloaded from TFS in a different machine works fine. I has to be something with my machine, but no idea of what...</p>