[worldofwarcraft]

You must have a different version of word from what I'm using at work. It doesn't even underline them nevermind give some odd replacement suggestion.

How about, "I that am king of this thread"?!

[gariharrr]

I've noticed that it often underlines it's, when used correctly ("it is"), because Word isn't smart enough to figure out if you mean it is or its possessive, and so it just reminds you that it could be the other way around. Maybe it's the case with that's as well? Is Thats (possessive) a word? I guess so, firefox thinks it is anyway.

[fissasste]

And the prize goes to Lord Shiva...except "I that am not" still seems grammatically incorrect to me; "I who am not" is surely preferable.

[halyshitzob]

Originally posted by Lorizael
More likely than the two of you having different versions of Word, you probably just have different settings for your grammar checker. The grammar checker is very customizable, but there's no setting that allows it to be correct. There's always the 'off' setting.