'Mark a post as solution' missing

Noticed earlier that the option to mark a post as 'Solution' is missing...
Has the option been disabled?

oem

not knowingly by me.

It's an option that needs to be turned on per category - not sure we have it turned on everywhere.

Which category are you looking in?

I can't see it here in Meta, or in Lounge, but wasn't aware that the setting was per category...