bug#8195: 24.0.50; 24.0.50; Strange buffer recentering behavior on M-x, apparently recently introduced

[Andreas Rottmann]

Start "emacs -Q" from bzr (I'm using the git mirror, most recent commit
is from Sun Mar 6 02:53:51 2011 -0800 by Paul Eggert, message "Merge:
current_column: ...").  Open a longish text file; etc/CONTRIBUTE from
Emacs source will do.  Navigate down the buffer so that point is on the
last visible line (and you still have a few screenfuls of text below
point).  Now hit "M-x".  The effect is that the text shown in the
buffer's window is changed so that the point position is centered
vertically in that window.

Until recently, this would not have any recentering effect.  It seems
that scrolling in general is behaving strangely (text shown in the
windows changing randomly) recently, but the above steps seem to always
reproduce to what I deem buggy behavior.



In GNU Emacs 24.0.50.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.20.1)
 of 2011-03-07 on delenn
Windowing system distributor `The X.Org Foundation', version 11.0.10904000
configured using `configure  '--prefix=/home/rotty/.system/stow/emacs''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: de_AT.UTF-8
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: C
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
C-x RET r e p o <backspace> C-g M-x r e p o r t - e 
m <tab> <return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Quit

Load-path shadows:
None found.

Features:
(shadow sort mail-extr message sendmail regexp-opt rfc822 mml easymenu
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045
ietf-drums mailabbrev mail-utils gmm-utils mailheader emacsbug url-util
url-parse auth-source eieio byte-opt bytecomp byte-compile assoc
gnus-util time-date password-cache url-vars mm-util mail-prsvr tooltip
ediff-hook vc-hooks lisp-float-type mwheel x-win x-dnd tool-bar dnd
fontset image fringe lisp-mode register page menu-bar rfn-eshadow timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
frame cham georgian utf-8-lang misc-lang vietnamese tibetan thai
tai-viet lao korean japanese hebrew greek romanian slovak czech european
ethiopic indian cyrillic chinese case-table epa-hook jka-cmpr-hook help
simple abbrev loaddefs button minibuffer faces cus-face files
text-properties overlay md5 base64 format env code-pages mule custom
widget hashtable-print-readable backquote make-network-process dbusbind
dynamic-setting system-font-setting font-render-setting move-toolbar gtk
x-toolkit x multi-tty emacs)