[JustSayNoToNannies]

As was already pointed out to you, you have to have some minimal level of education in the English language to use spell check (for instance, you have to know the difference between there, their, and they're).

I've already responded that spelling is not the same thing as grammar.

Irrelevant - the point is that you won't get the right spelling if you can't pick it out from among multiple possibilities offered by the spell checker (or if you can't tell when the spell checker defaults to the wrong option).

[Durus]

It is certainly relevant as grammar has constantly been conflated with spelling in this thread. Using the possessive pronoun “their” for the contraction “they're” is a grammar mistake, just like using “effect” for “affect” or “your” for “you're”. A spelling mistake would be using “thiers” for “theirs”. As I said there are plenty of people that don't spell particularly well (or type poorly) that understand grammar.