Double thanks Puntuado con 5 de 5 estrellas
Thanks for bringing our attention -- mine, anyway -- to this privacy-related "bug", and thanks for fixing it until it be taken care of in coming version(s) of Firefox.
Indeed I knew nothing of sites being aware of copying/pasting on their pages. You learn every day.
I'll have to take the author's word for it since I have no way, not being in the business, to check efficiency of this add-on, hoping there is no side-effect.