title: How come overflow:hidden works on a div but not a fieldset in firefox?
body: <p>I have a fieldset that looks like this:</p>
  
  <pre><code>&lt;fieldset&gt;
      &lt;input&gt;&lt;label&gt;tada&lt;/label&gt;
      &lt;input&gt;&lt;label&gt;tada&lt;/label&gt;
  &lt;/fieldset&gt;
  
  fieldset{
      overflow: hidden;
      height: 20px;
  }
  
  input{
      display: block   
  }
  </code></pre>
  
  <p>Js-fiddle:</p>
  
  <p><a href="http://jsfiddle.net/GWdWy/1/" rel="nofollow">http://jsfiddle.net/GWdWy/1/</a></p>
  
  <p>how come the fieldset shows all it's containing elements, whilst if I change the fieldset to a div:
  <a href="http://jsfiddle.net/GWdWy/2/" rel="nofollow">http://jsfiddle.net/GWdWy/2/</a></p>
  
  <p>the overflow hidden works.</p>