title: Animate WPF Text when binding updates, how?
body: <p>I want to be able to create a fade animation on a text element when the
  binding to that element updates. In other words, the effect is that as
  text gets added to a text box one sees a fading effect as the text updates
  and then fades out. I do'nt know how to achieve this. I have seen something similar
  using an <code>EventTrigger</code> on a <code>RoutedEvent</code> such as <code>FrameworkElement.Loaded</code> but how does one detect when a binding updates?</p>
  
  <p>Thanks.</p>