title: How do I make NavigationItem UIBarButtonItems visually acknowledge a touch?
body: <p>I have a UINavigationController where I initialize the NavigationBar as such (using MonoTouch):</p>
  
  <pre><code>NavigationBar.BarStyle = UIBarStyle.Black;
  NavigationBar.TintColor = UIColor.Black;
  </code></pre>
  
  <p>On a UIViewController that I subsequently push onto the navigation controller, I add a button as such:</p>
  
  <pre><code>NavigationItem.RightBarButtonItem = new UIBarButtonItem(UIBarButtonSystemItem.Add, (s, e) =&gt; HandleAddItem());
  </code></pre>
  
  <p>However, when I touch the button, it doesn't change color/shade (i.e. animate) to signify it's been touched. Similar UIBarButtonItems added to a manually-created UINavigationBar on another view controller (plain UIVIewController) animate as I'd expect.</p>
  
  <p>How can I get the navigation bar buttons to "flash" when they are on a UIViewController that has been pushed onto a UINavigationController?</p>