Pop a target (sprite, movie, thread) name s1.
Pop a first Boolean b2, which, when true, means that the mouse pointer is locked to the center of the object being dragged.
Pop a second Boolean b3, which when true means that the mouse pointer is constrained to the specified rectangle1 (n4 to n7, representing y2, x2, y1, x1.)
Once this function was called, the object attached to the mouse pointer will follow the mouse until a Stop Drag action is applied or another object is defined as the object being dragged with another Start Drag.