one we need, and then make copies as needed. This avoids lots of
extra loading (which can be slow, even with refcounted data; lots of path
lookups, etc). (Trying to get this to the point where we can construct new
OptionRows for a menu without making a whole new menu.) This approach
means we don't lose the potential to have different sTypes of OptionRow
in a single menu. (The annoying bit is that any actor we copy has to handle
copying, which is tricky for ActorFrame and doesn't work yet for AutoActor.
Working on it ...)