i had that problem earlier today, and made a big mistake. They been doing updates, just clear your cache and you should see that it's back.
Sorry, if i made you clear your cache for nothing. I know they moved the ABC button, but it really wasn't there earlier yesterday.
This is what i've noticed. You have to click on ABC, Then the misspelled words are underlined, left click on the underlined word and suggestions pop up. However, if none of the suggestions are correct. You have to click on ABC, to get out of that mod.
What were they thinking? Was the Spell Check on a list of items that needed improving?
NOW, it needs improving!
The perils of replying on computer spell checkers... see how many wrong spellings you can spot here (a spell checker will NOT help you!):