bug#13723: 24.2.93; Fringe icons corrupt buffer separator line

[Eli Zaretskii <eliz@gnu.org>]

> From: Glenn Morris <rgm@gnu.org>
> Cc: David Engster <deng@randomsample.de>,  13723@debbugs.gnu.org
> Date: Fri, 15 Feb 2013 14:30:57 -0500
> 
> Eli Zaretskii wrote:
> 
> > Unfortunately, I cannot reproduce this here, neither with stock Emacs
> > 24.2 nor with the current trunk.  I get a perfectly drawn border.
> 
> I see the issue in emacs-24 and trunk. x86_64 GNU/Linux, Lucid toolkit.

Do you see it in previous versions, like 24.2 and 23.3?  That will
tell us how urgent it is to fix this.

If this is a regression that needs to be fixed ASAP, can you trace
through the code which draws the border and see what goes wrong there?
The immediate suspects are those parts that reference the
redraw_fringe_bitmaps_p flag, and the x_draw_vertical_window_border
function.

Another possible way to see whodunit is to step through update_window
and update_window_line, and see which code removes the portions of the
vertical line.

Or maybe the problem is in the order in which fringe bitmaps and the
vertical border are drawn.