Doesn't work in Thunderbird Rated 1 out of 5 stars

Why is this add-on listed within the Thunderbird add-ons? It adds a search option in Firefox. It works great in Firefox - but that's not what I was looking for - I want something that works the same as Babelfish in Firefox - where I double click on a word in Thunderbird and a little window pops up with a translation. I already have this functionality in Firefox - so why put this add-on under Thunderbird add-ons - please review which mozilla product that this add-on should be listed under - FIREFOX not THUNDERBIRD!!!!!!!