For sites wishing to let the customer choose the booking duration!
This new feature lets the customer select a slot, then drag it to whatever duration they require. This behavior would typically be desirable for booking meeting rooms and such.
You can set the snap level to have the adjusted booking always end on 5,10,15,30,60 minutes. Set at the resource level so you can have some resources with adjustable slots and others not.
It works like Service based duration but you don't need to define multiple services to provide different durations.
This feature is introduced in beta 3 of 4.0.2, February 2017.
Demo it here, (Meeting Room A)