title: How to automatically scroll ScrollViewer - only if the user did not change scroll position
body: <p>I would like to create the following behaviour in a <code>ScrollViewer</code> that wraps <code>ContentControl</code>:<br/>
  When the <code>ContentControl</code> height grows , the <code>ScrollViewer</code> should automatically scroll to the end. This is easy to achive by using <code>ScrollViewer.ScrollToEnd()</code>.
  <br/>However, if the user uses the scroll bar, the automatic scrolling shouldn't happen anymore. This is similar to what happens in VS output window for example.</p>
  
  <p>The problem is to know when a scrolling has happened because of user scrolling  and when it happened because the content size changed. I tried to play with the <code>ScrollChangedEventArgs</code>of <code>ScrollChangedEvent</code>, but couldn't get it to work.</p>
  
  <p>Ideally, I do not want to handle all possible Mouse and keyboard events.</p>