Sometimes you may have tasks that have no specific start and end time scheduled. These tasks are called All Day Tasks. When a task lasts for more than one day, and you see it in a Day Calendar view, it is also an All Day Task, because the time has not been set for the tasks.

The all day tasks are displayed at the top of the calendar. You can make a task to be an All Day Task by dragging it to the top part of the calendar. If you drag it to the time slot area, it will be automatically scheduled to the timeslots you dragged it into.