Reading the reviews, it seems like this add-on has a common problem that, when Firefox changes its UI, this add-on can break the updated UI, until the add-on's updated for the new version.
At the moment (FF29.1) I cannot see any of my menu items with this add-on enabled, since it hides the menu, and yet does not show it in the titlebar. This may well be something I'm doing wrong, but until I figure it out, I can't use this add-on. Which is a shame: 29.1 really needs it.
To disable the add-on if you are affected by this, since the missing menu means you can't get to the tools->addons, you will need to go to the URL "about:addons".