title: Chosen plugin not updating dynamic content
body: <p>I am using  <a href="http://harvesthq.github.io/chosen/" rel="nofollow">http://harvesthq.github.io/chosen/</a> in multiple mode and it dosen't seem to update after submitting. All I get is a blank input box and in the dropdown, the entry I just submitted is still there. I know the entry is getting submitted because of the json return. If I refresh the page, the entry is no longer in the dropdown and the default I use is there. Where have I gone wrong with my coding.</p>
  
  <p>Many thanks</p>
  
  <pre><code>$("#box_rtv").val('Choose a box...').trigger("chosen:updated");
  </code></pre>
  
  <pre class="lang-html prettyprint-override"><code>&lt;select data-placeholder="Choose a box..." class="chosen-select required" multiple="multiple" style="width:250px;" name="box_rtv[]" id="box_rtv"&gt;
  </code></pre>