Re: master 5b5608c614: Fix glyph skipping optimization when a tab line is enabled

[Eli Zaretskii]

> From: Po Lu <luangruo@yahoo.com>
> Cc: emacs-devel@gnu.org
> Date: Mon, 18 Apr 2022 16:23:34 +0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Maybe not, but why should such subtle assumptions be implicitly
> > embedded in the code, when you have specific flags to do the job?  A
> > glyph matrix has both header_line_p and tab_line_p flags, so comparing
> > to their sum should do the job cleanly, I think.
> 
> Yes, I already installed such a change, but I asked that question for
> future reference.

I think the answer is YES, but the condition is enforced in window.el,
so it isn't necessarily "carved in stone".