I have also observed this in other split window configurations, e.g. the
Summary and Article buffers in Gnus.  The missing scroll bar appears as
soon as the lower window is made current.  I have also seen the scroll
appear spontaneously after a few seconds, but I haven't found a way to
reproduce that.  The bug occurs only if the above sexps are in
user-init-file; it does not occur after evalling them after starting
with -Q, or loading them from the command line.

This bug is present in all pretest builds I have, but the earliest of
these is only from 2010-01-13.  It is not present in the last
pre-pretest build I have, from 2009-11-27.

I don't know how to debug this, but if someone can guide me, I'll try.


In GNU Emacs 23.1.91.4 (i686-pc-linux-gnu, GTK+ Version 2.18.1)
 of 2010-01-28 on escher
Windowing system distributor `The X.Org Foundation', version 11.0.10605000
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=local
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t