title: Unresolved project references only on first load of a solution
body: <p><strong>Short description:</strong> First load of a solution will mark external project references as invalid, reloading the solution fix the problem.</p>
  
  <p><strong>Detailed description:</strong></p>
  
  <p>We have a large amount of C# projects in our system, with several different solutions containing only a small number of projects. The projects are referencing each other via project references instead of direct reference to the dll. The referenced projects are not part of the solution.</p>
  
  <p>I experience a strange behavior when using these solutions: every time I open a solution for the <strong>first time</strong>, these external project references are marked as <em>invalid</em> under the References tree, and some features are not working properly (for example Code analysis, ReSharper references, etc.) Building the solution is possible without errors. However, when I <strong>reload</strong> the solution, all references will be <em>valid</em> again.</p>
  
  <p>Additional infos:</p>
  
  <ul>
  <li>If I change something in one of the project file, which triggers a reload of the project in the solution, the references are broken again, and I have to reload the solution twice to fix them.</li>
  <li>If I add the external projects to the solution, than the problem does not appear.</li>
  <li>If I close Visual Studio and load the last solution on next start, the references will be valid. Only loading another solution triggers the problem.</li>
  </ul>
  
  <p>Although the problem is not crucial, it is very inconvenient and time consuming.</p>
  
  <p>We are using Visual Studio 2010 and .NET 4.0 (Visual Studio 2012 is also installed).</p>