What do you think about making skylines consider the grob properties
rotation and extra-offset?
(1) keep everything as it is
(2) skylines should reflect both grob rotation and grob extra-offset
(3) skylines should reflect grob rotation only
(4) skylines should reflect grob extra-offset only
Obviously, (1) is sub-optimal and (2) and (4) would make extra-offset
useless in many standard cases because it has been designed for arbitrary
shifting around and shouldn't be hampered by skylines and it should be
possible to make grobs overlap by using extra-offset.
But skylines taking grob rotation into account would be a good idea,
wouldn't it?