Dragging in from outside

A palette of services beside two droppable calendars in <CalendarExternalDrops>: drag a service onto a time (a long-press on touch), or pick it up with Space, a click or a tap and place it with the arrow keys and Enter or a click on a time. Image files dropped from the desktop book photo shoots. acceptExternal narrows what each calendar takes, a rule refuses drops outside opening hours with its reason, and a placeholder waits for the booking a fake API adds, or rejects.