title: D3 issue in IE9
body: <p>I have an simple issue with D3 in IE9.</p>
  
  <p>Have a look at this example both in Chrome/Firefox and IE9.
  --> <a href="http://bl.ocks.org/d/1005873/" rel="nofollow">http://bl.ocks.org/d/1005873/</a></p>
  
  <p>Click on one block to use the zoom functionality. 
  It works on Chrome, but IE9 is not able to "hide" all the other elements when zooming. The content out of the "div" block is shown.</p>
  
  <p>I am wondering how this issue can be solved. One way is to integrate the chart in a iframe, like on this page : <a href="http://bl.ocks.org/1005873" rel="nofollow">http://bl.ocks.org/1005873</a></p>
  
  <p>but I was wondering if there was a better way to set D3 in order to avoid the iframe workaround.</p>
  
  <p>Thanks a lot.</p>