Screen flickers with high CPU usage in Emacs unicode 2 branch

[Leo]

[It is on a laptop's LCD screen]

I noticed Emacs unicode 2 branch has something weird but was not able
to reproduce the bug until today. I falsely reported this bug to
emacs-w3m list: http://article.gmane.org/gmane.emacs.w3m/6658. It
might contains useful information if you cannot reproduce the bug by
the following:

  1.  emacs -q
  2.  C-u 32 M-x hanoi

Now you will see the screen flickers like crazy and my laptop CPU was
put to its full speed.


In GNU Emacs 23.0.0.7 (i686-pc-linux-gnu, X toolkit)
 of 2007-03-29 on sl392.st-edmunds.cam.ac.uk
Windowing system distributor `The X.Org Foundation', version 11.0.70101000
configured using `configure  '--prefix=/usr/local/packages/emacs23' 
'--with-kerberos5' '--enable-locallisppath=/usr/local/share/emacs/site-lisp' 
'--without-toolkit-scroll-bars' '--with-xft' '--enable-font-backend' 
'--with-x-toolkit=yes''

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_GB.UTF-8
  value of $XMODIFIERS: @im=none
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t

Major mode: Group

Minor modes in effect:
  gnus-topic-mode: t
  gnus-undo-mode: t
  rcirc-track-minor-mode: t
  dired-omit-mode: t
  recentf-mode: t
  icomplete-mode: t
  show-paren-mode: t
  delete-selection-mode: t
  global-auto-revert-mode: t
  display-time-mode: t
  shell-dirtrack-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
<down> <down> <down> <down> <down> <down> <down> <down> 
<down> <down> <down> <down> <down> <down> <down> <down> 
<down> <down> <down> <down> <down> M-w C-x m z h a 
o <tab> <backspace> <backspace> <backspace> <backspace> 
<backspace> <down> <down> <down> <down> <down> C-y 
C-u 3 C-k C-k C-k C-x 1 <down-mouse-4> <mouse-4> <double-down-mouse-4> 
<double-mouse-4> <triple-down-mouse-4> <triple-mouse-4> 
<down-mouse-4> <mouse-4> <down-mouse-4> <mouse-4> <double-down-mouse-4> 
<double-mouse-4> <down-mouse-1> <mouse-1> C-a C-o C-o 
<down-mouse-4> <mouse-4> <double-down-mouse-4> <double-mouse-4> 
<help-echo> <help-echo> M-x b b d b <return> j i z 
e <return> C-x o C-u C-o p h o <tab> <return> C-k M 
o <tab> <return> 0 7 9 1 7 3 5 5 1 0 2 <return> b c 
h u a n <return> <down> C-u e <return> <C-backspace> 
0 7 7 0 3 7 2 4 3 1 4 <return> q 0 7 7 2 5 0 2 8 1 
6 9 C-x 1 <help-echo> <down-mouse-4> <mouse-4> <double-down-mouse-4> 
<double-mouse-4> <down-mouse-4> <mouse-4> <double-down-mouse-4> 
<double-mouse-4> <down-mouse-5> <mouse-5> <double-down-mouse-5> 
<double-mouse-5> <triple-down-mouse-5> <triple-mouse-5> 
C-c C-k y C-c C-k y y q g <help-echo> <help-echo> <down-mouse-1> 
<mouse-2> <down-mouse-1> <mouse-2> <help-echo> <down-mouse-5> 
<mouse-5> <down-mouse-4> <mouse-4> <double-down-mouse-4> 
<double-mouse-4> <help-echo> <down-mouse-1> <mouse-1> 
<down-mouse-1> <down-mouse-1> <mouse-2> <help-echo> 
<down-mouse-5> <mouse-5> <down-mouse-5> <mouse-5> <double-down-mouse-5> 
<double-mouse-5> <down-mouse-4> <mouse-4> <double-down-mouse-4> 
<double-mouse-4> <triple-down-mouse-4> <triple-mouse-4> 
q <return> <return> <help-echo> <down-mouse-5> <mouse-5> 
<help-echo> <down-mouse-5> <mouse-5> <down-mouse-5> 
<mouse-5> <double-down-mouse-5> <double-mouse-5> <triple-down-mouse-5> 
<triple-mouse-5> <triple-down-mouse-5> <triple-mouse-5> 
<down-mouse-4> <mouse-4> <double-down-mouse-4> <double-mouse-4> 
<triple-down-mouse-4> <triple-mouse-4> <triple-down-mouse-4> 
<triple-mouse-4> <triple-down-mouse-4> <triple-mouse-4> 
<triple-down-mouse-4> <triple-mouse-4> <triple-down-mouse-4> 
<triple-mouse-4> <triple-down-mouse-4> <triple-mouse-4> 
q <up> <up> <up> <up> <up> L <down-mouse-5> <mouse-5> 
<double-down-mouse-5> <double-mouse-5> <down-mouse-1> 
<mouse-1> M-g p <return> <return> q l g <down-mouse-4> 
<mouse-4> <double-down-mouse-4> <double-mouse-4> <down-mouse-5> 
<mouse-5> <down-mouse-4> <mouse-4> <double-down-mouse-4> 
<double-mouse-4> <triple-down-mouse-4> <triple-mouse-4> 
z y <down-mouse-4> <mouse-4> <double-down-mouse-4> 
<double-mouse-4> <help-echo> d <down-mouse-5> <mouse-5> 
<down-mouse-5> <mouse-5> <down-mouse-4> <mouse-4> <double-down-mouse-4> 
<double-mouse-4> C-x b g r <return> M-x r e p o <tab> 
o <backspace> r <tab> b <tab> <return>

Recent messages:
Saving /home/leo/GNUS/.newsrc.eld...done
byte-code: Beginning of buffer [2 times]
Press any key to resume from typing break.
Loading hanoi...done
Press any key to resume from typing break.
Mark set
byte-code: Beginning of buffer
Making completion list...
Loading emacsbug...done
call-interactively: End of buffer [2 times]