title: How to make Style.Triggers trigger a different named style to be applied
body: <p>Lets say I have the below:</p>
  
  <pre><code>&lt;Style TargetType="{x:Type TextBox}"&gt;
      &lt;Setter Property="BorderThickness" Value="1" /&gt;
      &lt;Setter Property="BorderBrush" Value="Gray" /&gt;
      &lt;Style.Triggers&gt;
          &lt;Trigger Property="IsFocused" Value="true"&gt; 
              &lt;Setter Property="BorderBrush" Value="Green" /&gt;
              &lt;Setter Property="BorderThickness" Value="2" /&gt;
          &lt;/Trigger&gt;
      &lt;/Style.Triggers&gt; 
  &lt;/Style&gt;
  </code></pre>
  
  <p>This works fine and there is nothing too much wrong here, but it is a fairly simple case. What happens if I want to have the IsFocused style state listed as a exsplicit style how do reference that style as being the IsFocused style, i.e. </p>
  
  <pre><code>&lt;Style x:key="ActiveStyle" TargetType="{x:Type TextBox}"&gt;
      &lt;Setter Property="BorderBrush" Value="Green" /&gt;
      &lt;Setter Property="BorderThickness" Value="2" /&gt;
  &lt;/Style&gt;
  
  &lt;Style TargetType="{x:Type TextBox}"&gt;
      &lt;Setter Property="BorderThickness" Value="1" /&gt;
      &lt;Setter Property="BorderBrush" Value="Gray" /&gt;
      &lt;Style.Triggers&gt;
          &lt;Trigger Property="IsFocused" Value="true"&gt;
             -- Here I want to reference ActiveStyle and not copy the copy the setters
          &lt;/Trigger&gt;
      &lt;/Style.Triggers&gt; 
  &lt;/Style&gt;
  </code></pre>