title: flex4 list and layout dragging animation
body: <p>I found a blog about the list drag-drop animation:<a href="http://rialitycheck.com/demos/spark/layoutdemo.html" rel="nofollow">drag-list-animation-demo</a>, the blog is here:
  <a href="http://www.rialitycheck.com/blog/index.cfm/2011/3/3/Animating-Spark-List-Items" rel="nofollow">blog about the drag animation</a>
  Unfortunately, This blog has no source code, so anyone know how to implement like the effect?</p>