> It sometimes appears as in the attached screenshot with an artifact
 > on the right of the fringe.

Actually the problem is deeper and seems to go back to my pixelwise
changes from last year.  Starting Emacs 24.4 with -Q can get me the
attached screenshot when dragging the divider between two side-by-side
windows.  IIUC this means that we don't align the first column of R2L
text correctly at the right edge of a window that is not the rightmost
one.  Do you understand what goes wrong here?

martin