aqaqaqaqaqq Rated 3 out of 5 stars

where is the appearance in the menu bar?
it was very useful.

This review is for a previous version of the add-on (5.1.0). 

menubar

It has been replaced with the new "PrefBar menu button". See here:
http://prefbar.mozdev.org/images/screenshots/prefbar_menu.png
As this may be placed to anywhere in the toolbars and not just to the menubar, this should be more useful than a static menubar item.