title: Can't get underline to show up when triggered
body: <p>I have the following style, but when the mouse over trigger is true, no underline shows up on the text. </p>
  
  <pre><code>&lt;Style x:Key="HyperlinkToggleButtonStyle" TargetType="ToggleButton"&gt;
      &lt;Setter Property="Template"&gt;
          &lt;Setter.Value&gt;
              &lt;ControlTemplate TargetType="ToggleButton"&gt;
                  &lt;TextBlock x:Name="TextBlock"&gt;
                              &lt;ContentPresenter Content="{TemplateBinding  Content}" ContentTemplate="{TemplateBinding  ContentTemplate}"/&gt;
                  &lt;/TextBlock&gt;
              &lt;/ControlTemplate&gt;
          &lt;/Setter.Value&gt;
      &lt;/Setter&gt;
  
      &lt;Style.Triggers&gt;
          &lt;Trigger Property="IsMouseOver" Value="false"&gt;
              &lt;Setter Property="Background" Value="{StaticResource StandardBackground}"/&gt;
              &lt;Setter Property="Foreground" Value="Black" /&gt;
              &lt;Setter Property="FontSize" Value="12"/&gt;
              &lt;Setter Property="FontStyle" Value="Normal"/&gt;
              &lt;Setter Property="FontWeight" Value="Normal"/&gt;                                         
          &lt;/Trigger&gt;
  
          &lt;Trigger Property="IsMouseOver" Value="true"&gt;
              &lt;Setter Property="Background" Value="{StaticResource StandardBackground}"/&gt;
              &lt;Setter Property="Foreground" Value="{StaticResource StandardBlue}" /&gt;
              &lt;Setter Property="Cursor" Value="Hand" /&gt;
              &lt;Setter Property="FontSize" Value="12"/&gt;
              &lt;Setter Property="FontStyle" Value="Normal"/&gt;
              &lt;Setter Property="FontWeight" Value="Normal"/&gt;
              &lt;Setter Property="TextBlock.TextDecorations" Value="Underline"/&gt;
          &lt;/Trigger&gt;
      &lt;/Style.Triggers&gt;
  &lt;/Style&gt;
  </code></pre>