Some glitches in repainting (example: rectangle attached to frame)

[davidedc]

steps:

• create a frame
• create a rectangle
• attach the rectangle to the frame so it's only partially inside the frame, like so:
  

obtained:

• moving the frame causes the rectangle to sort of break like so:
  

expected:

• the rectangle should be clipped at the frame edge as soon as attached to the frame, like so:
  

(This is fixed in Zombie Kernel but it would need bisecting to find the fix since I fixed this long ago)