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 (1.5.1-signed). 

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.