title: React: ref is not a prop
body: <p>When using React.js</p>
  
  <p>Why do I get <code>`ref` is not a prop</code> &amp; <code>`key` is not a prop.</code> error </p>
  
  <p>Notes</p>
  
  <ul>
  <li>however I do not get this error running with webpack-dev-server.</li>
  <li>I do not have <code>ref</code> or <code>key</code> defined in any of my react components.</li>
  </ul>