Puntuado con 4 de 5 estrellas

For me it worked fine too till FF45 Update came out. Could the author please patch this so it works again?

Esta valoración es de una versión anterior del complemento (1.7.5.1-signed). 

This bug should be fixed in 1.7.6 version, released now.
A workaround is to set the preference "extensions.profileswitcher.use_onbeforeunload" to false, but I suggest to try before the new version.