在 2019年12月30日 +0800 PM7:27，Alan Third <alan@idiocy.org>，写道：

Hi, I can’t replicate this. I suspect it’s something in your config
slowing redisplay enough for bug#32932 to appear.

It is 100% reproducible on my machine with or without my config. The machine is macbook pro 2016. The OS is macOS 10.13.6.

There is a record video in the attachment.

Can you try the branch scratch/ns/draw-to-bitmap and see if the same
issue occurs there?

I can’t reproduce the problem with this branch.