title: Overflow: overlay doesn't work in firefox
body: <p>On my website I need to use the css property <code>overflow: overlay</code> for a <code>&lt;div&gt;</code>.</p>
  
  <p>However, it is not rendering in the browser and an inspection of the css in firebug shows that it isn't even there, but it is as it works in Chrome. I havn't tested out safari.</p>
  
  <p>What must I change to get the <code>overflow: overlay</code> css property working?</p>
  
  <p>Thanks</p>