title: updating the selection model and proxy model after insertion into a custom model in qt
body: <p>I have a model in which i will be adding symbols dynamically.
  I am using a proxy model and a selection model for linking with the view
  Every time i add a symbol to my source model the proxy model gets updated but the selection model i set for the view gets screwed up.
  It doesn't recognize any selections anymore
  can someone tell me why ??</p>
  
  <pre><code>void SymbolViewer::on_openButton_clicked()
  {
      this-&gt;selModel = ui-&gt;symbolListView-&gt;selectionModel();
       ...
  }
  </code></pre>
  
  <p>i set the selection model each time my i click a button to work on the selection.</p>