Fine

Even though I've installed the plug in, Firefox still uses US English and it's diving me nuts! Very frustrating experience.

This is NOT British English.
realise or realize? British is realise, American is realize. So why does it say realise is wrong? And there are a bunch of other British words labeled as wrong.

Obwohl ich 2-sprachig bin, hilft es mir, Schreibfehler zu verhindern

Not compatible?

Prático.