bug#17124: 24.3.50; Occasional Extremely Slow Redraws in OSX Emacs

[Eli Zaretskii]

> From: Eric Froemling <ericfroemling@gmail.com>
> Date: Fri, 27 Jun 2014 10:30:04 -0700
> Cc: Eli Zaretskii <eliz@gnu.org>,
>  17124@debbugs.gnu.org
> 
> I generally run into the slowdown maybe once every half-hour during 
> real-world usage; a common trigger seems to be mouse clicks, drags, or 
> scrolls, though I haven’t been able to pin down any predictable repro. cases 
> aside from the shake-the-divider one.
> 
> As a janky workaround, I’ve found that switching to a different desktop and 
> back during a slow redraw allows all the buffered draws to go through 
> instantly; not sure if that implies anything useful.

I know almost nothing about this stuff, but it surely smells like some
issue with the backend, not with Emacs.