title: Apply style to first child?
body: <p>Is there some way to apply styles to the first (or last or nth) child of a container (anything that contains children)? I am trying to customize the look of tab items so that the first one has different border radius than the others.</p>
  
  <p>This is what I have now:</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;ControlTemplate TargetType="{x:Type TabItem}"&gt;
      &lt;Grid&gt;
          &lt;Border Name="Border" BorderBrush="#666" BorderThickness="1,1,1,0" CornerRadius="8,8,0,0" Margin="0,0,0,-1"&gt;
              &lt;TextBlock x:Name="TabItemText" Foreground="#444" Padding="6 2" TextOptions.TextFormattingMode="Display"&gt;
                  &lt;ContentPresenter x:Name="ContentSite" VerticalAlignment="Center" HorizontalAlignment="Center" ContentSource="Header" Margin="12,2,12,2"/&gt;
              &lt;/TextBlock&gt;
          &lt;/Border&gt;
      &lt;/Grid&gt;
  &lt;/ControlTemplate&gt;
  </code></pre>