title: Binding Button IsEnabled to ComboBox Selection
body: <p>I know this can be done in a converter, but I'd like to disable a button based on a particular item selected in a ComboBox, using only XAML. </p>
  
  <p>The following below works, using the Visibility property. How come if I try to use IsEnabled it does not work? Is there something I'm missing? If that's the way it is, if someone could explain why, that would be great. Should I just always use converters?</p>
  
  <pre><code>&lt;ComboBox Name="WidthTypeComboBox" 
      ItemsSource="{Binding Source={StaticResource WidthType}}" 
      SelectedItem="{Binding WidthTypeSelected}" /&gt;
  </code></pre>
  
  <p>Works:</p>
  
  <pre><code>&lt;Button Content="Map Channels" Command="{Binding ShowChannelAction}"&gt;
      &lt;Button.Style&gt;
          &lt;Style TargetType="Button"&gt;
              &lt;Style.Triggers&gt;
                  &lt;DataTrigger Binding="{Binding SelectedIndex, 
                      ElementName=WidthTypeComboBox}" Value="0"&gt;
                      &lt;Setter Property="Visibility" Value="Visible" /&gt;
                  &lt;/DataTrigger&gt;
              &lt;/Style.Triggers&gt;
          &lt;/Style&gt;
      &lt;/Button.Style&gt;
  &lt;/Button&gt;
  </code></pre>
  
  <p>Does not work:</p>
  
  <pre><code>&lt;Button Content="Map Channels" Command="{Binding ShowChannelAction}"&gt;
      &lt;Button.Style&gt;
          &lt;Style TargetType="Button"&gt;
              &lt;Style.Triggers&gt;
                  &lt;DataTrigger Binding="{Binding SelectedIndex, 
                      ElementName=WidthTypeComboBox}" Value="0"&gt;
                      &lt;Setter Property="IsEnabled" Value="True" /&gt;
                  &lt;/DataTrigger&gt;
              &lt;/Style.Triggers&gt;
          &lt;/Style&gt;
      &lt;/Button.Style&gt;
  &lt;/Button&gt;
  </code></pre>