title: Unable to add project reference in Visual Studio 2015
body: <p>I previously asked a similar question regarding Visual Studio 2013 but now I'm running into the same problem with Visual Studio 2015 but it seems to work differently, which makes the previous answer not applicable to this question. This is my previous question: <a href="https://stackoverflow.com/questions/27745835/visual-studio-2013-how-to-debug-a-project-within-a-solution">Visual Studio 2013 - How to debug a project within a solution</a></p>
  
  <p>I'm attempting to add a project reference. I have a library I'm working on in a separate solution/project and a console application I want to use to test and debug the library.</p>
  
  <p>I tried: Add Reference > Projects > Solution > Browse</p>
  
  <p>But the open file dialog does not contain .sln files in the filter list and if I force it to display them by typing *.sln and then select the Solution I get:</p>
  
  <p>"Please make sure the file is accessible and that it is a valid assembly or COM component."</p>
  
  <p>What am I doing wrong? How do I properly add a Solution/Project reference?</p>
  
  <p><a href="https://i.stack.imgur.com/o6rYA.png" rel="noreferrer"><img src="https://i.stack.imgur.com/o6rYA.png" alt="enter image description here"></a></p>