Understanding why the time does not change when dragging
When you drag an untimed task to another position in the Schedule, after another untimed task, no time will be assigned to the dragged task. When you drag an untimed task to another position, after a timed task, the dragged task is set to the same time as the task before it. Even if the task before it has a duration, this will not affect this behaviour.
This is in order to avoid possible anomalies in the ordering and timing of tasks, for example sending them to the following day (and therefore appearing to disappear altogether), or preventing the presentation of overlapping tasks which sometimes need to be viewed together.