title: Deleted project folders/files remain in VSO/TFVC and the file system
body: <p>I had a solution containing the following projects:</p>
  
  <ol>
  <li>Web App 01  </li>
  <li>Server Control Foo</li>
  <li>Server Control Bar</li>
  </ol>
  
  <p>Each project has its own directory in the root of the solution directory, directly mirroring the structure of the solution.  </p>
  
  <p>I branched the solution, then combined items 2 &amp; 3 into a new project within that solution, then deleted projects 2 &amp; 3.  I committed the changeset.  The resulting structure in VS2015 solution explorer was this:</p>
  
  <ol>
  <li>Web App 01</li>
  <li>Server Control Library</li>
  </ol>
  
  <p>I then merged the branch, and committed this also.  Over time, branching and merging has got slower and slower.  On inspecting the file structure of my hard drive, and Visual Studio Online, I see this folder structure:</p>
  
  <ul>
  <li>Web App 01  </li>
  <li>Server Control Foo</li>
  <li>Server Control Bar</li>
  <li>Server Control Library</li>
  </ul>
  
  <p>Despite Solution Explorer not listing the deleted projects, the folders and files from all my deleted projects remain.  Despite their status, they are also being branched every time.  Is this the correct behaviour, and is it safe to delete them?  If so, should I delete using VSO, Windows, or VS2015?</p>