This might not sound too clever, but why don't we just make the extend
property be determined by the first character in the line rather than
the last character / newline character? 

On Tue, Sep 12, 2023, at 3:51 PM, Kévin Le Gouguec wrote:
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > tags 65896 wishlist
> > thanks
> 
> This seems related to bug#52587, maybe so much so that it might make
> sense to merge them?  IIUC, given this Org buffer…
> 
> --8<---------------cut here---------------start------------->8---
> * foo
> #+begin_stuff
> bar
> #+end_stuff
> * baz
> --8<---------------cut here---------------end--------------->8---
> 
> … and folding "* foo",
> 
> * bug#52587 is about "#+end_stuff"'s :extended background "bleeding
>   into" the header line,
> 
> * bug#65896 (this report) is about the header line's :extended
>   background getting "cut short" once folded.
> 
> AFAIU those are two aspects of the same problem people have with
> outlines: the effective :extended background comes from the last line of
> the folded content (because that's the newline that is actually
> displayed) whereas one might expect it to come from the header line (but
> it can't, because the header line's newline is invisible).
> 
> So I'd expect addressing one report will also address the other.
> 
> >> From: StrawberryTea <look@strawberrytea.xyz>
> >> Date: Tue, 12 Sep 2023 13:00:45 -0500
> >> 
> >> 
> >> Hi. This issue comes from Reddit,
> >> https://www.reddit.com/r/emacs/comments/v0i4js/extend_org_heading_background_face_past_the/.
> >> Basically, if I fold text using text properties, the heading background
> >> does not extend to the end of the window. To quote /u/yantar92: "This is
> >> because the trailing newline in the folded heading gets hidden. If the
> >> trailing newline is invisible, :extend t has no effect. It is Emacs
> >> limitation, AFAIK." It would be great if we could make the :extend
> >> property work with invisible text.
> >
> > It cannot.  Text properties of invisible text are ignored because the
> > display engine skips invisible text and doesn't consider it and its
> > properties at all.
> >
> > I'm not closing this bug in the hope that someone will have a clever
> > idea for how to work around this, or maybe (gasp!) even submits a
> > patch.
>