title: How to set z-index on a component?
body: <p>Tried using the 'zindex' prop, as suggested here:
  <a href="https://github.com/facebook/react/issues/1456" rel="noreferrer">https://github.com/facebook/react/issues/1456</a></p>
  
  <pre><code>&lt;Input ref="username" type="text" label="Username" 
  placeholder="Enter username" zindex={1} /&gt;
  </code></pre>
  
  <p>Doesn't work. Also tried 'zindex="1"'</p>
  
  <p>Any ideas?</p>