> I also checked the diacritics (tashkil): It seems that they do not take up
> column number in Emacs.
> In gedit, cursor movement is similar, but the vowels there do take up column
> number (as for cursor movement, as in emacs: forwards/backwards skips them,
> while 'delete' handles them separately). I find this behavior more
> consistent with the way both programs handle the lam-alef ligature (one
> cursor-movement space, but two column numbers).
> However, as I said, I do not know which behavior is the most natural for
> Arabic users.
In Emacs, the column number affects when a user types C-n
(or C-p) to go to (roughly) the same x-position of the next
(or previous) line. So, the column number should reflects
the x-position, and for that, zero-width combining
characters should not be counted into the column number. Of
course, when a text is displayed by a variable-pitch font,
it is not good to use the column number for such a purpose,
but that is what Emacs has been done for long.
The lam-aref ligature case should be fixed so that the
ligature glyph is counted as one-column.
It seems that gedit uses the actual x-pixel-position to move
the cursor down. It will be better Emacs does the same in