You can't use drag&drop on the same sprite.
Create another (invisible) sprite with Drag&Drop behavior, say "dragSprite".
Remove Drag&Drop behavior from the "sangStick".
Change events to this:
dragSprite is dragging -> set AreaAngle to angle(sangPad.X, sangPad.Y, dragSprite.X, dragSprite.Y)
.................set AreaDistance to distance(sangPad.X, sangPad.Y, dragSprite.X, dragSprite.Y)
The rest is the same.
When not dragging, return both sangStick and dragSprite to sangPad posision.