title: Why insertBefore, on this scenario, delete my element?
body: <p><a href="http://jsfiddle.net/yp9LT/2/" rel="nofollow noreferrer">Code</a> :</p>
  <h1>HTML</h1>
  <pre><code>&lt;div class=&quot;try&quot; id=&quot;try1&quot;&gt;1&lt;/div&gt;
  &lt;div class=&quot;try&quot; id=&quot;try2&quot;&gt;2&lt;/div&gt;
  &lt;div class=&quot;try&quot; id=&quot;try3&quot;&gt;3&lt;/div&gt;
  </code></pre>
  <h1>jQuery</h1>
  <pre><code>var ImmagineDrag=$('#try3');
  var ImmagineDrop=$('#try2');
  
  var swap1 = ImmagineDrag.index();
  var swap2 = ImmagineDrop.index();
  
  ImmagineDrag.insertBefore($('.try').eq(swap2));
  ImmagineDrop.insertBefore($('.try').eq(swap1));
  </code></pre>
  <p>why the div <code>try2</code> will be removed from the DOM?</p>