Curved Bezier link, use mouse we can change the two guide points to adjust curviness, good, but
add (comment out) this fromSpot and toSpot,
fromSpot: go.Spot.Right, toSpot: go.Spot.Left,
line 29
then the two guide points are gone, I can’t change the curviness,
https://jsfiddle.net/batobolg/5bf42q9d/2/
why it don’t work?