title: (Py)Qt - QTreeView, Model, insert row
body: <p>I am little bit confuse.
  I am working with QTreeView as model I assigned QSortFilterProxyModel.
  <a href="http://www.riverbankcomputing.co.uk/static/Docs/PyQt4/html/qsortfilterproxymodel.html" rel="nofollow">http://www.riverbankcomputing.co.uk/static/Docs/PyQt4/html/qsortfilterproxymodel.html</a></p>
  
  <pre><code>//treeview
  self.ProxyView = QtGui.QTreeView(self.centralwidget)
  
  //model
  self.ProxyModel = QtGui.QSortFilterProxyModel(self)
  self.ProxyModel.setSourceModel(QtGui.QStandardItemModel(0, 3, self))
  
  //assign model to tree
  self.ProxyView.setModel(self.ProxyModel)
  </code></pre>
  
  <p>On button click I want to add row to this tree.</p>
  
  <p>Here is my slot
      def pushButton_addRow(self):
          self.ProxyModel.insertRow(0)
          self.ProxyModel.setData(self.ProxyModel.index(0,0), "hi")</p>
  
  <p>It doesnt work, it works only for first row, then I added empty rows. But wenn I fill second cell it works.</p>
  
  <pre><code>self.ProxyModel.setData(self.ProxyModel.index(0,1), "hi")
  </code></pre>
  
  <p>Any Idea?</p>