This is because the NGRegion code will adjust the Shape object based on center / scale shape, but Region does not. However Region has to implement the picking logic. If Region knew about NGShape of the shape it was supplied, it could then do the shape resizing technique on the Region level and pass the resized shape down to the NGRegion (essentially pulling a chunk of logic from NGRegion up into Region). Region then could have accurate picking for shapes when pickOnBounds is set to false.