Automatic Scrolling

If the target location for a drag operation is outside of the 3D view, the mouse pointer can be moved to an edge of the view, where the view will pan automatically up, down, left or right according to the 3D view edge that the mouse pointer hits. The mouse pointer must move in order for the panning to continue which may necessitate you making a small movement of the pointer near to the view edge to keep the pan operation going.