Rated 4 out of 5 stars

Ciao,

me too after many dis/enabling of all my addons
have discovered the bug on bm button w/ FF13
as signaled by Michael2012 bizhkom and denniscuddles.

But ,waiting for a real fix from Milly, i've also tried some biz
and found that crazily a previous version work better
apparently w/o that bug.
Thus for me ,under Unix/Linux, CM2-4.0 is fine w/ FF13.

Moreover you have to disable the compatibility check
coz that version is declared working only for FF3.0 - 4.0b8pre ...

GoodFoxing
Sandro