Got it. There is setter code in the library and I was overriding it. Here is the fixed code:
from scene import Scene, SpriteNode, run, EffectNode
class pt(SpriteNode):
def __init__(self, **kargs):
SpriteNode.__init__(self, 'plf:HudX', **kargs)
self.scale = 0.5
class plot (SpriteNode):
def __init__(self, **kargs):
SpriteNode.__init__(self, **kargs)
self.anchor_point = (0, 0)
self.color = '#8989ff'
class test(Scene):
def setup(self):
clip = EffectNode(parent=self)
clip.crop_rect = (0, 0, self.size.x / 2, self.size.y / 2)
pane = plot(parent=clip)
pane.size = (self.size.x / 2, self.size.y / 2)
clip.position = (50, 50)
for x in (50, 100, 150, 200, 250, 300, 350, 400):
p = pt(parent=pane)
p.position = (x, x)
if __name__ == '__main__':
tst = test()
run(tst)
```