title: Is binding IsEnabled optional when binding Command?
body: <p>I noticed that the following code:</p>
  
  <pre><code>&lt;Button Content="_Timbres..." 
      Command="{Binding Path=ShowTimbresCommand}" 
      IsEnabled="{Binding Path=CanExecuteShowTimbresCommand}"/&gt;
  </code></pre>
  
  <p>behaves equally as:</p>
  
  <pre><code>&lt;Button Content="_Timbres..." 
      Command="{Binding Path=ShowTimbresCommand}"&gt;
  </code></pre>
  
  <p>Meaning that the CanExecuteShowTimbresCommand is automatically bound to the IsEnabled property.
  Is that true and why?</p>