title: ListView's item insert animations in WinRT
body: <p>Recently I started building my own big Windows 8 Store App.
  Working on UI I started replicating some good UIs.</p>
  
  <p>One I met very interesting animation of inserting new elements in list view in standard Mail app. When you click on chain it expands and shows all messages in chain. </p>
  
  <p><a href="http://www.youtube.com/watch?v=gwnp7E9OBhY" rel="nofollow">Here</a> is captured video.</p>
  
  <p>I have no idea what technique did they use to achieve this animation and behavior.</p>
  
  <p>Can anyone help me, explain or give example how can I achieve such behavior? Thanks.</p>