On Tue, 02 Nov 2021 09:58:31 +0800 Po Lu <luangruo@yahoo.com> wrote:

> Eli Zaretskii <eliz@gnu.org> writes:
>
>> I see that xterm does something special in x_draw_relief_rect when the
>> line width is exactly 1 pixel, and w32term.c doesn't do that.  maybe
>> that's the problem.
>
> That isn't related, it only serves to make buttons look nicer and have
> more contrast by drawing a black line outside a relief rect.
>
> FWIW, this bug doesn't manifest in 27.2.

With the following patch I no longer see the display glitch: