Documentation for ido-mode is not very enlightening

[era]

This is the text of a bug which I filed against Ubuntu originally.
See https://bugs.launchpad.net/ubuntu/+source/emacs22/+bug/180130
The Ubuntu emacs22 maintainer suggested I report it here instead.
Sorry if this ends up with duplicates or something.

Here's the documentation string for the function "ido-mode":

  ido-mode is a variable defined in `ido.el'.
  Its value is nil

  Documentation:
  Determines for which functional group (buffer and files) ido behavior
  should be enabled. The following values are possible:
  - `buffer': Turn only on ido buffer behavior (switching, killing,
    displaying...)
  - `file': Turn only on ido file behavior (finding, writing, inserting...)
  - `both': Turn on ido buffer and file behavior.
  - `nil': Turn off any ido switching.

  Setting this variable directly does not take effect;
  use either M-x customize or the function `ido-mode'.

  You can customize this variable.

  [back]

Browsing the source file ido.el (provided you have the elisp source
package installed) reveals a lengthy commentary about what this mode
does and how to invoke it .... in comments. It would be beneficial if
this description could be available directly or indirectly as
user-accessible documentation.


In GNU Emacs 22.1.1 (i486-pc-linux-gnu, GTK+ Version 2.12.0)
 of 2007-11-06 on terranova, modified by Ubuntu
Windowing system distributor `The X.Org Foundation', version 11.0.10300000
configured using `configure  '--build' 'i486-linux-gnu' '--host' 
'i486-linux-gnu' '--prefix=/usr' '--sharedstatedir=/var/lib' 
'--libexecdir=/usr/lib' '--localstatedir=/var' '--infodir=/usr/share/info' 
'--mandir=/usr/share/man' '--with-pop=yes' 
'--enable-locallisppath=/etc/emacs22:/etc/emacs:/usr/local/share/emacs/22.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/22.1/site-lisp:/usr/share/emacs/site-lisp:/usr/share/emacs/22.1/leim'
 '--with-x=yes' '--with-x-toolkit=gtk' 'build_alias=i486-linux-gnu' 
'host_alias=i486-linux-gnu' 'CFLAGS=-DDEBIAN -DSITELOAD_PURESIZE_EXTRA=5000 -g 
-O2''

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_DK.UTF-8
  locale-coding-system: utf-8
  default-enable-multibyte-characters: t

Major mode: Text

Minor modes in effect:
  display-time-mode: t
  tooltip-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:
<help-echo> C-x b 0 0 <tab> <backspace> <backspace> 
C-g C-x C-f . e m <tab> . <tab> a u <tab> <return> 
<down> <down> <down> v <escape> x g l o <tab> s e <tab> 
<return> C-c C-f f i n d - f i l e - a <tab> <return> 
C-x ( C-x C-g C-x ( C-c C-f <return> C-x b <return> 
<down> <down> C-x ) C-x e <escape> 0 C-x e C-x k <return> 
C-x k <return> C-x 4 b e m <tab> <return> C-x 5 b 0 
0 <tab> <return> <switch-frame> <switch-frame> <switch-frame> 
<switch-frame> <escape> x r e p o r t - e m <tab> 
<return>

Recent messages:
Starting new Ispell process...
Note: file is write protected
uncompressing morse.el.gz...done
Note: file is write protected [2 times]
uncompressing ido.el.gz...done
Note: file is write protected [2 times]
uncompressing README.gz...done
Note: file is write protected [2 times]
line-move-1: End of buffer
Loading emacsbug...done