title: column-count on fieldset doesn't work for firefox
body: <p>I'm trying to do a multi-column layout for a form with multiple pairs of label and input. It works fine in Chrome and IE, but I can't get it to work with Firefox. (<a href="http://jsfiddle.net/6CmJb/2/" rel="nofollow">demo of the problem</a>).  I tried removing the <code>clear: left</code> on the <code>label</code>, but that doesn't help.</p>
  
  <p>Here's the simplified HTML:</p>
  
  <pre><code>&lt;fieldset&gt;
      &lt;label&gt;Label 1&lt;/label&gt;
      &lt;input type="number" value="0" /&gt;
      &lt;label&gt;Label 2&lt;/label&gt;
      &lt;input type="number" value="0" /&gt;
      ...
  &lt;/fieldset&gt;
  </code></pre>
  
  <p>Here's the CSS:</p>
  
  <pre><code>fieldset {
      height: 110px;      
      border: none;
  
      column-count: 2;        
      -moz-column-count: 2;
      -webkit-column-count: 2;    
  }
  
  label {
      float: left;
      clear: left;
      width: 125px;
      text-align: right;
      padding: 3px 0 3px 0;
      margin: 2px 0 2px 0;
  }
  
  input {
      float: left;
      width: 50px;
      height: 20px;
      margin: 3px 0 3px 10px;
  }
  </code></pre>
  
  <p>I also tried using <code>columns</code> and no luck.  Is there rules that I didn't add that is required for Firefox?</p>