title: WPF GridSplitter visiblity
body: <p>I have a problem regarding GridSplitter visiblity.</p>
  
  <p>In this, whatever I am hosting a Winform DataGridView. The GridSplitter, when dragged is properly visible on other controls. But not on this grid. In fact, whatever I host instead of Datagridview, becomes the topmost control, which makes the GridSplitter hide behind it.</p>
  
  <pre><code>&lt;Grid&gt;
      &lt;Grid.RowDefinitions&gt;
          &lt;RowDefinition Name="rowForButton"/&gt;
          &lt;RowDefinition Name="rowForGridSplitter" Height="Auto" MinHeight="81" /&gt;
      &lt;/Grid.RowDefinitions&gt;
      &lt;Button Grid.Row="0" Height="50" Width="110" Content="Button in First Row"/&gt;
      &lt;my:WindowsFormsHost Panel.ZIndex="0" Grid.Row="1"  Margin="30,11,138,0" x:Name="winHost" Height="58" VerticalAlignment="Top" OpacityMask="Transparent"&gt;            
          &lt;win:DataGridView x:Name="dataGridView"&gt;&lt;/win:DataGridView&gt;
      &lt;/my:WindowsFormsHost&gt;        
      &lt;GridSplitter  BorderThickness="1" Panel.ZIndex="1" Grid.Row="1" HorizontalAlignment="Stretch" Height="5" ShowsPreview="True" VerticalAlignment="Top"&gt;
      &lt;/GridSplitter&gt;
  &lt;/Grid&gt;
  </code></pre>