title: Way to detect when a child is removed from a DisplayObjectContainer?
body: <p>Is there a way to detect when a child is removed from a DisplayObjectContainer? I tried overriding removeChild(), but this doesn't appear to trigger when the child is removed by adding it to another container (via a call to addChild() on the new container). I'm not aware of any events that trigger, either...</p>
  
  <p>I know that you can do this with higher-level Flex classes, but I'm using a Pure AS3 project.</p>