Assegnate 2 su 5 stelle

I followed these instructions:-
To enable, right-click in a multi-line text box, select "Languages", then "English / United Kingdom"
It then switches to English (UK) for my message, BUT next time I type it's reverted to English (US)
Really annoying! I'm on FF v9.0 in Win7 64-bit

Questa recensione riguarda una versione precedente (1.19.1) del componente aggiuntivo.