bug#44826: 27.1; Display artifacts which stay on the screen when scrolling

[Eli Zaretskii]

> Date: Mon, 23 Nov 2020 19:47:33 +0000
> From: novim via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> 1. save this package which makes org tables pretty by putting unicode 
> characters onto regular org table
> characters
> 
> https://raw.githubusercontent.com/Fuco1/org-pretty-table/master/org-pretty-table.el
> 
> 2. eval it, so you get org-pretty-table-mode
> 3. download the attached org file
> 4. open it and go to the first character of table
> 5. turn on org-pretty-table-mode, the table should be switched to pretty mode
> 6. before the first character of the table type a space, so the header row is 
> shifted by one character to the
> right
> 7. the display artifacts should appear at the top of the window
> 8. if you press cursor up until the window starts scrolling then you can see 
> parts of the artifact staying on the
> screen during scrolling

The problem doesn't happen here, neither 7 nor 8.

Could it be some problem with your video driver?  If it has some
"optimization" features, disable them and try again.

> Pretty table mode uses jit for highlight, it might be an issue with jit. I 
> assume it's some kind of emacs
> problem, because of the artifact staying in place while scrolling.

Artifacts that stay put while scrolling are a sign that Emacs's
display engine doesn't know they are there.  Which usually means some
problem outside of Emacs control.