title: XAML Rectangle Property Trigger problem
body: <p>I have a WPF app with a Rectangle trigger defined as:</p>
  
  <pre><code>&lt;Style TargetType="{x:Type Rectangle}"&gt;
     &lt;Setter Property="Rectangle.StrokeThickness" Value="1"/&gt;
     &lt;Style.Triggers&gt;
        &lt;Trigger Property="IsMouseOver" Value="True"&gt;
           &lt;Setter Property="Rectangle.StrokeThickness" Value="4"/&gt;
        &lt;/Trigger&gt;
     &lt;/Style.Triggers&gt;
  &lt;/Style&gt;
  </code></pre>
  
  <p>And a Rectangle as:</p>
  
  <pre><code>&lt;Rectangle Fill="Blue" StrokeThickness="2" Stroke="Black" Height="20" Width="50" /&gt;
  </code></pre>
  
  <p>Rectangle doesn't change strokethickness when mouse is over. Why not?</p>