title: VirtualizingPanel in DataGrid
body: <p>I've started exploring the Data and UI virtualization features in WPF recently and stumbled upon something strange. </p>
  
  <p>I created a <code>DataGrid</code>'s with <code>Virtualizing</code> enabled and filled it with a list with 1,000,000 items. This works great and amazingly fast. </p>
  
  <pre><code>&lt;Grid&gt;
      &lt;DataGrid x:Name="employees" VirtualizingPanel.IsVirtualizing="True" 
                                   VirtualizingPanel.IsContainerVirtualizable="True"
                                   VirtualizingPanel.VirtualizationMode="Recycling"/&gt;
  &lt;/Grid&gt;
  </code></pre>
  
  <p>However, when I nested it under a <code>StackPanel</code> it loads for over a minute until I get <code>OutOfMemoryException</code>. I've set the same <code>VirtualizingPanel</code> properties on the <code>StackPanel</code> as well but it doesn't help. </p>
  
  <p>Is this behaviour intentional or am I missing something basic here? And how can I manage to support data virtualization in nested controls?</p>