You run spell check? It's automatic for me, they show up as red underlining that need to be manually corrected. Perhaps it's an account setting somewhere that you can change, snoop around in your profile/system settings whatever is available on the account page, reminds me I need to do the same.
I hate auto correct with a passion and don't allow it on any software that I use, notification of error is sufficient cause you can't learn if you don't correct your mistakes after all, many names and some technical terms that are acceptable in industry aren't in the dictionary.