Don't know if this's a bug or just a matter of refining the Doff system, but, in some cases you have a mission listed which requires some specific officer, e.g. Security Officer (specifically that, not a plain Security one) - and the mission is listed available even tho all such officers are either in duty, or in Sickbay. Slight nuissance at most, but I'd like it this way:

- if officers are on a mission, or are assigned to ship duty, or are in sickbay, they'd be considered "unavailable".

EDIT: make it so that there's a toggle in options or somewhere so that folks in Ship Duty could be considered available, as I think some people might like them being counted (I wouldn't, as I have a solid ship duty which very rarely needs changing and I like them being excluded from available folks).