bug#51550: 29.0.50; Customize Group INS buttons sometimes don't have a left box line

[Po Lu]

Eli Zaretskii <eliz@gnu.org> writes:

> So I guess someone will have to step through the relevant drawing code
> and see where do those two border lines come from.  I cannot do this
> because the problem doesn't exist on my system.

It turns out that it's not a bug in the display code.  Bisect says:

commit 8b024a6ff10f7907445ea60c4db8355638616ed1
Author: Stefan Kangas <stefan@marxist.se>
Date:   Mon Mar 15 00:27:20 2021 +0100

    * lisp/wid-edit.el (widget-field): Add subtle border to face.

 lisp/wid-edit.el | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Thanks.