bug#45620: 28.0.50; Child frames should have their own border width and colour

[martin rudalics]

> Ok, all done now, see attached patch.

Looks good.

> For the copyright I have asked my employer to make sure that the
> copyright parts from my contract don't apply to the work I do on my own
> time like this, but most of the company will still be on holidays or on
> sick
> leave, so it could be a few days before I get an answer.

Let's hope for the best.

Thanks, martin