Please describe the problem:
Nautilus thumbnails files while they are still being downloaded, moved or changed, which results in some exploding memory usage and slower operation

Steps to reproduce:
1. download a movie file into a directory which is open in nautilus
2. observe the icon changing from generic .avi to a thumbnail and back
3. Try the same thing moving a folder of avi's of photos


Actual results:
It thumbnails the file as soon as it changes

Expected results:
I'd expect it to respect the fact that the file is being manipulated and wait for the file or operation to be completed

Does this happen every time?
yes

Other information:
Ubuntu 6.0.6.1, nautilus 2.14.3