title: Why won't IsChecked change on this toggle button?
body: <p>I have the following xaml for a toggle button:</p>
  
  <pre><code>&lt;ToggleButton Margin="0,3" Grid.Row="3" Grid.ColumnSpan="2" Command="{Binding DataContext.SelectAllCommand, Mode=OneWay, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}}"&gt;
    &lt;ToggleButton.Style&gt;
     &lt;Style TargetType="{x:Type ToggleButton}"&gt;
         &lt;Setter Property="Content" Value="Select All"/&gt;
         &lt;Style.Triggers&gt;
              &lt;Trigger Property="IsChecked" Value="True"&gt;
                  &lt;Setter Property="Content" Value="Select None"/&gt;
                  &lt;Setter Property="Command" Value="{Binding DataContext.SelectNoneCommand, Mode=OneWay, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}}"/&gt;
              &lt;/Trigger&gt;
            &lt;/Style.Triggers&gt;
        &lt;/Style&gt;
    &lt;/ToggleButton.Style&gt;
  &lt;/ToggleButton&gt;
  </code></pre>
  
  <p>But the <code>IsChecked</code> property never gets updated when clicking the button. </p>
  
  <p>If I use snoop and force the IsChecked to True then the trigger kicks in.</p>