bug#32932: 27.0.50; render bugs on macOS Mojave

[Eli Zaretskii]

> From: Aaron Jensen <aaronjensen@gmail.com>
> Date: Sun, 4 Nov 2018 09:12:55 -0800
> Cc: Eli Zaretskii <eliz@gnu.org>, 32932@debbugs.gnu.org, boris@d12frosted.io
> 
> If I log x/y in the erase, after pressing enter I see this:
> 
> erasing 456 133
> erasing 0 0
> erasing 456 0
> erasing 0 0
> erasing 456 0
> erasing 0 0
> 
> 456, 133 is where the cursor is in dired. Is it strange that it’s
> alternating between x coordinates?

Are these coordinates frame-relative or window-relative?  If the
latter, they could belong to more than one window.