The red zigzags under your words when you type them means they are spelled wrong. Just saying.
That doesn't explain why they pop up under words like "realise" and "manoeuvre" though. Just saying (yes, I know. The spellcheck is in American, not
real English, and it's not my computer, so I'm not allowed to fix it)
(P.S. Don't take my comment about American English seriously. In fact, very rarely take anything I say seriously, unless it's directly related to a game. I usually don't)