title: Use the DNX Core framework instead of DNX 451
body: <p>My <code>project.json</code> includes two frameworks: </p>
  
  <pre><code>"frameworks": {
    "dnx451": { },
    "dnxcore50": { }
  }
  </code></pre>
  
  <p>When running the app in Visual Studio via Debug > Start without debugging, Visual Studio uses <code>dnx451</code>. How do we ask Visual Studio to use <code>dnxcore50</code> instead?</p>
  
  <p>Here is what I have tried: </p>
  
  <ul>
  <li><strong>Build > Configuration Manager.</strong> There is no option to use one framework instead of another.</li>
  <li><strong>Property Pages</strong>. The Application, Build, and Debug areas do not offer an option to use one framework over another.</li>
  </ul>
  
  <p>The use case is to test CoreCLR while on a system that has the full framework. How do we do this? As a last result, I could comment out <code>dnx451</code> from <code>project.json</code>, though that seems like a hack.</p>