Use the Link Dummy Mechanism to update dummy and seat motion.
After changing the position of a dummy and seat, the seatbelt tool can
automatically update the full seatbelt system.
In the Entity Editor, activate the Link
Dummy Mechanism checkbox.
If the Link Dummy Mechanism is not activated, you can still update on demand
by right-clicking on the appropriate seatbelt system and selecting
Update from the context menu.