Hes absolutly right, if you have too many passive skilled sailors they will extend past the interface buttons where you cannot access the active ones.
Only way to deal with it that Im aware of is to 'retire' some of those passive. Why one would have a dozen diving specilists aboard at one time is beyond me.
Anyhow while in port swap them out for untrained or trained in other skills.
Now if someone could mod the UI so that the actives are listed first the problem kind of goes away.