Rated 4 out of 5 stars

Great addon!
Be aware that it does not have an 'icon' (as describe on this site).
You should add the button 'spellcheck' on toolbar to use it.

** But it is freezing firefox when I try to remove the icon, when I to drag the icon back from addon toolbar to 'customize' window **
(Firefox 13 / Ubuntu 12.04)

This review is for a previous version of the add-on (