I personaly think that the "select" option needs an overhaul. It can be very annoying to rotate a composite object by hand, but especially scaling composite objects.
Multiple item flipping/rotation/scaling just gets really complex with recreating all the bodies (required for scaling/flipping), joints, and positioning them. Similarly to why Custom Items can't be rotated/scaled on spawn.
 "Mutilate-a-Doll 2"){kind=icon}
 "Unity - Non-Euclidean Geometry Test"){kind=icon}
 "Trimps Preview"){kind=icon}
 "The Ultimate Game 2"){kind=icon}
Multiple item flipping/rotation/scaling just gets really complex with recreating all the bodies (required for scaling/flipping), joints, and positioning them. Similarly to why Custom Items can't be rotated/scaled on spawn.