scrolling an NSImageView leaves tracks

FROM : Geoff Levner
DATE : Sat Apr 09 21:53:41 2005

I have an NSImageView in an NSScrollView. I can zoom in and out,
scroll, load new images, and everything is fine.

Except for one thing. Sometimes, when a newly loaded image is initially
framed so that it is clipped by the scroll view, scrolling leaves
tracks (grey vertical or horizontal lines) where previously clipped
portions of the image become visible.  Zooming in or out once makes
them go away.  Calling the NSClipView's setCopiesOnScroll method with
NO also makes the problem go away, but then, of course, scrolling is
much slower.

Has anybody out there ever encountered this sort of behavior?