Can't get rid of about-correct

Make sure the focus is in the main text field of the composer when you look at the menu items. Does this help?

No. No matter where the cursor is, the option to correct spelling automatically remains shocked and greyed out. There is an option to correct which typing but the greyed out option remains ne matter where he cursor is.

Which OS are you using?

Newest on OS 10.10 Yosemitie

Anything new on this?

I had the same problem, I think you've to disable it in the main system configuration in macos:
System Preferences -> Keyboard -> Text -> disable automatically correct

After restarting Mailmate the greyed option is automatically disabled ..

Perhaps that's it?

best regards,
Martin