Hi:

Sorry for the big latency in my replies. Busy days.

>
>Mostly true (it could also be the "underlying" face when we render a
>display string).
>
You're right

>
>But if the default face has underline or overline or box etc.,
>attributes, we don't want to exit early, even though its background
>color is the default, right?
>
Then the simpler solution is the attached patch I have been using for
some days... It just extends the conditions in the if (as you suggested
since the beginning).

If it is fine for you, then you can commit the patch for me. Of just
tell me if there are more issues to fix.

Best,
Ergus