Firebug's element picker completely bugged

[DriftingSteps]

I... can't explain this. Please see for yourself.

http://i.imgur.com/CcxeXS2.png
Hovering on the h3 shows wrong location of the element on viewport.

Here's a live version of what's happening (.gif, 1.65mb)
http://i.imgur.com/7H1W8Vy.gif

This happens when I run pixel perfect with firebug. Firebug alone doesn't show any problem. Firebug continues becoming buggy unless I don't restart Firefox.
Also, is it possible to make a compact version?

Thanks.

[fflorent]

Thanks for the report. @janodvarko I could reproduce the issue. If you open Pixel Perfect, scroll down a bit and use the inspector, you get the problem.

Florent

[janodvarko]

I've reported platform bug at:
https://bugzilla.mozilla.org/show_bug.cgi?id=1168113

And committed a workaround.
The workaround can be removed as soon as the platform is fixed.

Honza