> Date: Sat, 13 Apr 2013 22:52:24 +0100
> From: E Sabof <esabof@gmail.com>
> Cc: 14200@debbugs.gnu.org

>
> > If you want the values you set be preserved for that buffer, you need
> > to set the buffer-local values of left/right-margin-width and
> > left/right-fringe-width.  If you want them to be preserved in a window
> > regardless of the buffer it displays, switch to another buffer by
> > invoking set-window-buffer with non-nil 3rd argument.
>
> Thanks, but changing those variables (or the corresponding fringe ones)
> doesn't seem to have any effect.

From the ELisp manual:

     Setting these variables does not immediately affect the window.
  These variables are checked when a new buffer is displayed in the
  window.  Thus, you can make changes take effect by calling
  `set-window-buffer'.