title: Change property on ListBox.SelectionChanged in XAML
body: <p>I want to write XAML code to change color of button when user changes selectionIndex of ListBox. How can I do it? I try</p>
  
  <pre><code>&lt;Trigger Property="IsSelectionChanged" Value="True"&gt;
      &lt;Setter TargetName="btnSave" Property="Background" Value="Red" /&gt;
  &lt;/Trigger&gt;
  </code></pre>
  
  <p>But property <code>IsSelectionChanged</code> is not found.</p>