title: overflow with z-index
body: <p>I have the following HTML markup</p>
  
  <pre><code>&lt;div id="main"&gt;
   &lt;div id="div1" style="position:relative;"&gt;&lt;/div&gt;
   &lt;div id="div2" style="z-index:-1; position:relative; overflow:auto; height:500px;"&gt;&lt;/div&gt; 
  &lt;/div&gt;
  </code></pre>
  
  <p>In <code>div2</code> I load data dynamically and the content could exceed the divs height, so I used a <code>overflow:auto</code> property to show a scrollbar. The problem is that the scrollbar appears in all browsers, but it is working just in IE8/9, FireFox and Chrome. In other browsers you see 
  the scrollbar, but without functionality.</p>