title: jqGrid TreeGrid loadonce and other issues
body: <p>I'm using jqGrid 3.7.2 and I'm rendering a treegrid.  The grid renders just fine however I have 2 major issues.</p>
  
  <ol>
  <li><p>loadonce=true doesn't seem to be working.  When I expand a node, it tries to load the data from the server even though I've already supplied all the data to the grid.  And that leads to my second issues...</p></li>
  <li><p>I can't collapse nodes.  The icon changes as if it is collapsed but I can see all it's children.  I've tried very simplistic data samples and can't get anything to work right.  Here is how I have my grid configured....</p></li>
  </ol>
  
  <p>(SO won't post JavaScript code for some reason)
  <a href="http://gist.github.com/522085" rel="nofollow noreferrer">http://gist.github.com/522085</a></p>
  
  <p>Generally, I'm returning JSON but I've also tried the same data sample using XML and get the same results.  Rendered tree but won't allow me to collapse nodes.</p>
  
  <pre><code> &lt;rows&gt;
      &lt;page&gt;1&lt;/page&gt;
      &lt;total&gt;1&lt;/total&gt;
      &lt;records&gt;1&lt;/records&gt;
      &lt;row&gt;
        &lt;cell&gt;1&lt;/cell&gt;
        &lt;cell&gt;Gregg&lt;/cell&gt;
        &lt;cell&gt;&lt;/cell&gt;
        &lt;cell&gt;&lt;/cell&gt;
        &lt;cell&gt;&lt;/cell&gt;
        &lt;cell&gt;&lt;/cell&gt;
        &lt;cell&gt;&lt;/cell&gt;
        &lt;cell&gt;&lt;/cell&gt;
        &lt;cell&gt;&lt;/cell&gt;
        &lt;cell&gt;0&lt;/cell&gt;
        &lt;cell&gt;1&lt;/cell&gt;
        &lt;cell&gt;2&lt;/cell&gt;
        &lt;cell&gt;false&lt;/cell&gt;
        &lt;cell&gt;true&lt;/cell&gt;
    &lt;/row&gt;
    &lt;row&gt;
        &lt;cell&gt;2&lt;/cell&gt;
        &lt;cell&gt;Bolinger&lt;/cell&gt;
        &lt;cell&gt;&lt;/cell&gt;
        &lt;cell&gt;&lt;/cell&gt;
        &lt;cell&gt;&lt;/cell&gt;
        &lt;cell&gt;&lt;/cell&gt;
        &lt;cell&gt;&lt;/cell&gt;
        &lt;cell&gt;&lt;/cell&gt;
        &lt;cell&gt;&lt;/cell&gt;
        &lt;cell&gt;1&lt;/cell&gt;
        &lt;cell&gt;1&lt;/cell&gt;
        &lt;cell&gt;&lt;/cell&gt;
        &lt;cell&gt;true&lt;/cell&gt;
        &lt;cell&gt;false&lt;/cell&gt;
    &lt;/row&gt;
  &lt;/rows&gt;
  </code></pre>
  
  <p>Any help would be much appreciated.</p>