bug#43835: 28.0.50; auto-hscroll-mode/current-line + show-paren-mode + gnus-summary-mode = bug

[Eli Zaretskii]

> From: Stephen Berman <stephen.berman@gmx.net>
> Cc: 43835@debbugs.gnu.org
> Date: Thu, 08 Oct 2020 10:39:38 +0200
> 
> > bidi-paragraph-direction is set to left-to-right in any descendant of
> > prog-mode, in particular in Emacs Lisp mode.  And yet I couldn't
> > reproduce this in a Lisp buffer, no matter what I tried.  So that
> > setting is not the only cause.
> 
> Strange, because when I replace the above sexp in step 1 by the
> following, I see the same problem at step 2:

I tried reproducing the problem in a real-life .el file, not in a
synthetic example with a single Lisp line.  That's why I said
bidi-paragraph-direction cannot be the only reason.

> > If you add a line of text before and after the Subject line you insert
> > in the recipe, does the problem go away?  It does here.  But then I
> > wonder whether this problem only happens in Gnus with the very first
> > or the very last line of the summary buffer.  If that's not so, I'm
> > probably missing something else.
> 
> I think I've only seen this on the last line in a Gnus summary buffer.
> This also holds for the new test case (also in Emacs Lisp mode): after
> evaluating the following sexp, I see the problem only on the last line:

OK, so I think the conditions for triggering the problem are well
understood, and we both have the same observations, thanks.