using mozilla when you click +rep button and hover over one of the many things above it(rate thread,search thread)it expands dunno how to explain it better just do it try it
Not really a glitch, just the way the software works. It opens a pop up window and that applies to all on the page. Hover over your username, it expands that too. Also search, quick links, etc.
As FenceWalker said, that's how vBulletin works. I've seen the same behaviour on every vB forum I've used. As the saying goes, "it's a feature, not a bug"