What the... Black rectangle thing on post!?

[Tom.K]

I was looking at malware removal threads (just to check it out) while all of sudden, at post http://forums.spybot.info/showthread.php?p=342275#post342275, somewhere near the signature a black rectangle came out. After some scrolling up and down that thing stays in same place (doesn't moves from signature)! And after 2-4 seconds, it disappeared...
I'm not sure is this some sort of browser or add-on fault...
Anyone has any idea what happened?
Used: FF 3.5.3, AdBlock Plus 1.1.1, NoScript 1.9.9.01.

[tashi]

Hello Tom,

Not showing for me. It could be a plugin you have installed, not sure. I have AdBlock Plus but not NoScript.