Wrong sequence for Arabic ligature marks(FC5E-FC62, FCF2-FCF4)

[Eli Zaretskii]

> Date: Fri, 18 Feb 2022 23:24:01 +0000
> From: Richard Wordingham via Unicode <unicode at corp.unicode.org>
> 
> On Fri, 18 Feb 2022 14:37:50 -0700
> Doug Ewell via Unicode <unicode at corp.unicode.org> wrote:
> 
> > The vast majority of characters in the Arabic Presentation Forms-A
> > and -B blocks should not be used. They exist for compatibility with
> > older platforms that did not implement proper Arabic shaping and
> > directionality. Instead, use normal Arabic letters from the regular
> > Arabic, Arabic Supplement, Extended-A, or Extended-B blocks.
> 
> Irritatingly, I had to use some of these characters just this week
> because the shaping in Arabic fonts for basic installations of Windows
> 10 and Ubuntu didn't include the ligatures we were discussing - in
> particular that of U+FCCA ARABIC LIGATURE LAM WITH HAH INITIAL FORM.
> (The ligature was germane to the discussion.)  Many of the ligatures are
> not essential for proper shaping. I've now found and lawfully installed
> a font that gives me the ligature from normal Arabic letters.

Which font is that, please?

And does anyone here know why the Courier New font on Windows XP does
produce the ligature from those two characters, but the same font on
Windows 10 doesn't?  Is this ligature somehow deemed inappropriate or
problematic?  I'm not asking about U+FCCA, I'm asking about the
display of the two characters U+0644 and U+062D -- should it ligate or
shouldn't it?

Thanks.