I played around a bit with the version of Stack Overflow to anonymous (not logged in) users, and I noticed the following behaviour (click on the image to see the full size version, some things are not easily visible in the smaller inline image):

[![Enter image description here](https://i.stack.imgur.com/BPxGc.gif)](https://i.stack.imgur.com/BPxGc.gif)

This bug only appears when one of the Jobs ads for a specific company is visible. Because Tim Post commented that he couldn't reproduced it, I got curious and tried to load Stack Overflow via TOR with my location in the US, and there I actually don't get any of these ads that trigger the bug. I only see them when my location is Germany.

One difference seems to be that these ads inject a stylesheet called `cp.min.css`, which isn't present without them and which does apply styles to the elements that move.