bug#19395: 25.0.50; Setting left fringe to 0 messes up window-width

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: Titus von der Malsburg <malsburg@posteo.de>,  19395@debbugs.gnu.org
> Date: Wed, 17 Dec 2014 16:34:41 -0500
> 
> >   |left-to-right continued line |⤶
> >   |/RIGHT-TO-LEFT CONTINUED LINE|
> 
> Why do you need the empty space at the end of the left-to-right line?

Because that empty space simply doesn't exist in the display line's
geometry, as far as the display engine is concerned.  Most of the
display engine is oblivious to the fact that an RTL line is reversed
on display, so it cannot do its job if some lines are longer than
others.