Subject: Re: bug#59947: 30.0.50; Underline of tab-bar face does not respect x-underline-at-descent-line

From: Eli Zaretskii <[email-masked]>
Date: Sat, 10 Dec 2022 21:44:24 +0200

> From: Gabriel <[email-masked]>
> Date: Sat, 10 Dec 2022 16:28:52 -0300
> 
> Eli Zaretskii <[email-masked]> writes:
> >
> > The x-underline-at-descent-line option is only supported for windows
> > that display buffers.  And the tab bar uses a pseudo-window that has
> > no buffer (like the tool bar in builds that don't have a
> > toolkit-provided tool bar).
> 
> Thanks for the explanation, Eli.  In this case, feel free to close this
> bug report.
> 
> So it works for tab-line because it is displayed in a "real" window,
> right?

Yes.  A tab-line is similar to the mode-line and a header-line, and
uses the same display routines.