Subject: bug#4979: 23.1.50; describe-text-properties produces *Help* buffer without back/forward buttons

From: Peter Dyballa <[email-masked]>
Date: Thu, 19 Nov 2009 22:23:31 +0100

Hello!

When executing describe-text-properties on some character a *Help*  
buffer is created or updated with some text content, for example:

	Text content at position 234:

	There is an overlay here:
	 From 234 to 246
	  font-lock-face       comint-highlight-prompt

	There are text properties here:
	  field                output
	  fontified            t
	  front-sticky         (field inhibit-line-move-field-capture)
	  inhibit-line-move-field-capture t
	  rear-nonsticky       t

Similarly C-u C-x = produces a *Help* buffer without [back] and/or  
[forward] buttons. No matter how often I repeat these two commands,  
no button is created. But when I run describe-variable or describe- 
function and a [back] button is created by them in *Help* buffer,  
then describe-text-properties (or C-u C-x =) kind of inherit this  
feature and create *Help* buffers with a [back] button.

Shouldn't all functions which overwrite the previous contents of  
*Help* buffer also insert that [back] button?

In GNU Emacs 23.1.50.1 (powerpc-apple-darwin8.11.0, GTK+ Version 2.18.2)
  of 2009-11-18 on Latsche.local
Windowing system distributor `The XFree86 Project, Inc', version  
11.0.40400000
configured using `configure  '--without-sound' '--without-pop' '-- 
with-dbus' '--with-libotf' '--with-xpm' '--with-jpeg' '--with-tiff'  
'--with-gif' '--with-png' '--x-libraries=/opt/local/lib' '--x- 
includes=/opt/local/include' '--enable-locallisppath=/Library/ 
Application Support/Emacs/calendar23:/Library/Application Support/ 
Emacs' 'PKG_CONFIG_PATH=/opt/local/lib/pkgconfig:/opt/local/share/ 
pkgconfig:/usr/local/lib/pkgconfig:/usr/lib/pkgconfig' 'CPPFLAGS=-no- 
cpp-precomp' 'CFLAGS=-ggdb3 -gfull -mtraceback=full -Wno-pointer-sign  
-H -pipe -fPIC -mcpu=7450 -mtune=7450 -mtune=G4 -fast -mpim-altivec - 
ftree-vectorize -foptimize-register-move -freorder-blocks -fthread- 
jumps -fpeephole -fno-crossjumping' 'LDFLAGS=-dead_strip - 
multiply_defined suppress''

Important settings:
   value of $LC_ALL: nil
   value of $LC_COLLATE: nil
   value of $LC_CTYPE: de_DE.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: de_DE.UTF-8
   value of $XMODIFIERS: nil
   locale-coding-system: utf-8-unix
   default enable-multibyte-characters: t

Major mode: Shell

Minor modes in effect:
   shell-dirtrack-mode: t
   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
   global-auto-composition-mode: t
   auto-composition-mode: t
   auto-encryption-mode: t
   auto-compression-mode: t
   line-number-mode: t
   transient-mark-mode: t

Features:
(shadow mail-extr message ecomplete rfc822 mml mml-sec password-cache
mm-decode mm-bodies mm-encode mailcap mail-parse rfc2231 rfc2047 rfc2045
qp ietf-drums mailabbrev nnheader gnus-util netrc time-date mm-util
mail-prsvr gmm-utils mailheader canlock sha1 hex-util hashcash
mail-utils emacsbug sendmail regexp-opt pp wid-edit shell comint ring
descr-text help-mode easymenu view tooltip ediff-hook vc-hooks
lisp-float-type mwheel x-win x-dnd font-setting tool-bar dnd fontset
image fringe lisp-mode register page menu-bar rfn-eshadow timer select
scroll-bar mldrag 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 text-properties
overlay md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote make-network-process dbusbind
font-render-setting system-font-setting gtk x-toolkit x multi-tty emacs)

--
Greetings

   Pete

Give a man a fish, and you've fed him for a day. Teach him to fish,  
and you've depleted the lake.