debugger buffer jumps from window to window

[Drew Adams]

I first reported this bug on 2005-09-01, subject "debugger changes
windows with every `d' command". I didn't characterize it precisely
enough, so Richard wasn't able to reproduce it. I now know that it
involves the *Completions* window.

emacs -Q

M-x debug-on-entry minibuffer-prompt-end

M-x forw TAB TAB

M-p [enters debugger]

Step through the debugger (`d'). With each step, the debugger window
changes position. The other buffer displayed is alternately
*Completions* and whatever buffer was current at the beginning. IOW,
instead of the debugger being opened in a new, third window, it takes
the place, alternately of each of the other buffers that were
displayed.

This is extremely annoying. I do a lot of work with minibuffer
functions, so I see this very often. I end up doing most of my
debugging in Emacs 20, simply because it doesn't have this annoying
bug.

The problem occurs only when buffer *Completions* is displayed and
perhaps only when you debug a function run from the minibuffer.

A solution would be to show all three buffers: *Completions*,
debugger, and original buffer, in three windows.


In GNU Emacs 22.0.50.1 (i386-msvc-nt5.1.2600)
 of 2006-07-19 on BOS-CTHEWLAP2
X server distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-msvc (12.00)'

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: ENU
  locale-coding-system: cp1252
  default-enable-multibyte-characters: t

Major mode: Dired by name

Minor modes in effect:
  encoded-kbd-mode: t
  tooltip-mode: t
  tool-bar-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  auto-compression-mode: t
  line-number-mode: t

Recent input:
M-x d e b u g - o <return> m i n i b u f f e r - p 
r o m p t - e n d <return> M-x f o r w <tab> <tab> 
<tab> <tab> <tab> M-p d d q <help-echo> <help-echo> 
<help-echo> <help-echo> <menu-bar> <help-menu> <re
port-emacs-bug>

Recent messages:
Loading debug...done
Making completion list...
Loading help-mode...done
Entering debugger...
Proceeding, will debug on next eval or call.
Entering debugger...
Proceeding, will debug on next eval or call.
Entering debugger...
Back to top level.
Loading emacsbug...done