The spelling checker is on but it doesn't work, at all. I tried it with all sorts of incorrectly typed out words, sentences but the result is the same - nothing happens. Also tried disabling "Check spelling as you type" and do a manual check by using the hotkey "F7", no luck. I don't know if this is only for me, but this is an essential feature and this is the main reason why I'm currently debating whether I should move to Onenote.