I recently flew a long haul 77W flight on CX and during descent I noticed that there was something flapping on the wing - it definitely looked wrong. Here's a short video I got of it (sorry it's not longer, the FAs were going around telling people to switch off electronic devices):

http://www.flickr.com/photos/83240106@N05/7627710710/

So my question to you all - is this normal? Should I have been worried?