[mch_nz]

Are you using an external keyboard?

I raised a bug for this issue and was told that OO currently supports Auto Suggest only not spell checking. Unfortunately Auto Suggest doesn't work with a bluetooth keyboard. So until either OO supports spell checking or Apple enable autosuggest with external keyboards I guess we just have to either put up with spelling mistakes or just use the internal keyboard.

If you are frustrated with this then please raise it with support, the more requests they get the higher the priority of a fix

Cheers,
Mark