bug#41187: 28.0.50; Flipped text

[Alan Third]

On Mon, Aug 17, 2020 at 03:17:32PM +0100, Wasim Abbas wrote:
> Update:
> 
> Just managed to reproduce it with `emacs -Q` I just had to scroll
> for almost 10 minutes for it to kick in. So ignore my init.el red
> herring.

Hi Wasim, sorry for the long wait.

I've been trying to make some improvements to the performance of the
Emacs NS port, and I think they may help with this problem. Of course,
I'm not 100% sure the new code works anywhere except my PC yet, but if
you could give it a go that would be helpful.

I've pushed to a branch on the Emacs repository called
scratch/ns/performance. Please give it a go and see if it

1. works at all.

2. fixes your issue.

Thanks!
-- 
Alan Third