When Maniphest query has more than a window long result, drag-and-drop tasks to arrange their priority is very hard.
Normally in a drag-and-drop system, when the dragged item reaches a screen edge, the content scrolls to the corresponding direction.
In Maniphest this is not the case. Because the scrolling doesn't automatically happen while dragging, the user has to repeat a sequence of dragging then scroll for multiple times.