title: Styling the Xceed ColumnManagerCell
body: <p>I'm interested in styling the column headers on an Xceed DataGrid.  The goal is to make the background color grey, with a dark grey border around each header column cell.  It seemed to me like the best way to do this was to style the ColumnManager:</p>
  
  <pre><code>&lt;Style TargetType="{x:Type xcdg:ColumnManagerCell}"&gt;
      &lt;Setter Property="Template" Value="{StaticResource ColumnManagerCellTemplate}"/&gt;
      &lt;Setter Property="BorderBrush" Value="#c5c5c5"/&gt;
      &lt;Setter Property="BorderThickness" Value="1,1,1,1"/&gt;
  &lt;/Style&gt;  
  </code></pre>
  
  <p>Using this template:</p>
  
  <pre><code>    &lt;ControlTemplate x:Key="ColumnManagerCellTemplate" TargetType="xcdg:ColumnManagerCell"&gt;
          &lt;Grid Background="LightGray" &gt;
              &lt;xcdg:DataCell Content="{TemplateBinding Content}"
                             HorizontalAlignment="Stretch"
                             VerticalAlignment="Center"
                             Background="LightGray"
                             HorizontalContentAlignment="Left"
                             VerticalContentAlignment="Center"
                             BorderBrush="DarkGray"
                             BorderThickness="2"/&gt;
          &lt;/Grid&gt;
      &lt;/ControlTemplate&gt;
  </code></pre>
  
  <p>The background color shows up correctly, as does the content, but I cannot get a dark grey border to show up around each cell.  (Or any color border at all.)  What am I missing?  Shouldn't the BorderBrush and BorderThickness properties control this?  They seem to work on the rest of the cells in the grid, but not the ColumnManagerCells.  </p>