The mode for testing whether a Draggable element is over the Droppable. Testing is done for both sides of the Draggable and Droppable.
Tolerance can be one of:
fit - the whole Draggable is over the Droppable;
intersect - at least half of the Draggable is over the Droppable;
pointer - the mouse pointer must be over the Droppable;
touch - the Draggable element overlaps Droppable by at least a pixel.