title: UnoWinUI DockPanel control
body: <p>The below DockPanel code works fine in the UNO UWP Project, but breaks in unoapp-winui.</p>
  <pre><code>xmlns:Custom=&quot;using:Microsoft.Toolkit.Uwp.UI.Controls&quot; 
  
  &lt;Custom:DockPanel Margin=&quot;0,5,0,0&quot; LastChildFill=&quot;True&quot;&gt;
  </code></pre>
  <p>Is there any toolkit available in Uno WinUI which supports DockPanel?</p>
  <p>Thanks</p>
  <p>Neeraj</p>