On 20. Jun 2022, 03:22 +0200, Po Lu <luangruo@yahoo.com>, wrote:
>
> Isn't that a bug, since scroll bars should only be judged for windows
> that are still reachable?

I'd say no:  Ns_judge_scroll_bars is called for a frame, and loops over EmascScroller subviews of that frame. I don't see how it is could be certain that all EmascScrollers reference a live Emacs window at that point.