bug#39188: 28.0.50; w32 cursor redisplay problem

[Eli Zaretskii]

> From: Fabrice Popineau <fabrice.popineau@gmail.com>
> Date: Tue, 21 Jan 2020 17:36:13 +0100
> Cc: 39188-done@debbugs.gnu.org
> 
> Only you can find this quickly.

Actually, I didn't find it quickly enough.  I wasn't aware we
hide/unhide the caret in a separate thread until I put a breakpoint
there, and GDB told me it was switching to another thread when the
breakpoint breaks.  That got me thinking...