The thing is, people here are accustomed to having stuff about computers written in America-speak, and don't have much trouble in understanding it. And there are some cases where the American spelling has become the accepted one in that context, even in English.

For example "program" meaning computer program is now seen as the correct spelling, even though "programme" is correct spelling in all other contexts. For example, we'd watch TV programmes, and but a programme when we went to the theatre.

That kind of thing means that spell checkers aren't necessarily too reliable. The one I'm using at present recognises both "program" and "programme" as valid spellings - but of course gives no indication of when they are correct and when they are wrong.

And that unreliability of spell-checkers as a guide to correct spelling applies to a lot of other words as well. For example, there are many words where "ce" and "se" are both correct - but they mean something different (eg licence and license). Again a word like "tire" is perfectly good (non-American) English for what happens when you get exhausted, but it wouldn't be right for the "tyre" on the wheel of a car.