Good add-on, one of the very few things that reminds me that I am still using a Mac when browsing on Firefox. If you prefer to use a trackpad or mouse or simply not conveniently accessible to a keyboard, this add-on is your thing. Or you are use the shortcut: Cmd+Ctr+D to instantly look up the word same as the force-click feature. It will show the word which the pointer is right on, not the one you highlighted.
Thanks for downloading this add-on. Please be assured that this add-on has no code that interferes with your trackpad. If you feel that some Firefox add-on is causing it, you can troubleshoot by using Firefox Safe Mode. Also, I would really appreciate if you could share the name of the site where it only brings up translation of 'function'. Thanks.