Puntuado con 5 de 5 estrellas

Very handy, thank you!
One request though: it will be better to add icons so it is easier to find some menus (open with for ex.)

Esta valoración es de una versión anterior del complemento (1.5). 

Indeed, it would be nice to show the context menu icons, but because of technical reasons this is pretty complicated. I don't think that it's really worth the trouble and would definitely like to keep the add-on as simple as possible for now.

Puntuado con 5 de 5 estrellas

Please update to Firefox 4 beta :)

Esta valoración es de una versión anterior del complemento (1.2). 

Yes, I know that the add-on should be updated for Firefox 4, but I've been too short on time lately (and I still am at the moment). I will have time to update the add-on in January/February, hopefully before the final release of Firefox 4.