Go to Workflow -> Appointments
Select a Schedule View
Select a single schedule from the Schedule drop down
Enter an appointment, starting at 9:00am, and ending at 9:30am.
Enter another appointment, with the same starting time as that previously
On return to the appointment browser, the second appointment will display immediately after the first, but starting at 9:30am.
A workaround would be to revert to the multiple-schedule style display when there are double bookings.
i.e. where there is a double booking add another column for the same time and schedule.