You are right. This variable fixed everything.

Thank you very much for your attention.

On Thu, Mar 10, 2022 at 9:18 PM Eli Zaretskii <eliz@gnu.org> wrote:

> [PLEASE keep the bug address on the CC list.]
>
> > From: hossein valizadeh <valizadeh.ho@gmail.com>
> > Date: Thu, 10 Mar 2022 20:53:49 +0330
> >
> > > Also, does this happen in "emacs -Q"?
> > Yes, it happens ...
> >
> > این‌ها
> >
> > ماه‌ها
> >
> > رفته‌ای
>
> OK, I see it now, thanks.
>
> I think what you want is to customize the variable
> arabic-shaper-ZWNJ-handling to the value 'as-space or maybe even
> 'absorb.  Then the display will be as you expect.
>
> FTR: Emacs 27 had a bug in the character composition/shaping rules for
> the Arabic script, and on my system the text you sent is displayed in
> Emacs 27 with glitches (when I move the cursor across the ZWNJ
> character, it leaves artifacts behind).  Emacs 28 fixes that problem,
> and that's why you see the difference.  By default, Emacs isn't
> supposed to display ZWNJ specially in Arabic shaping, but the above
> variable can change that, so I suggest you use it.
>
> Bottom line: I don't think there's a bug here.  You just don't like
> the default behavior, but an optional behavior like you want is
> available.
>