bug#16822: 24.3.50; show-paren-mode adds confusion to active region

[yynyygy@gmail.com]

When show-paren-mode is on, it adds confusion to the active
region. Suppose I have some text which is (hello),

1. I set the region to (hello and place the cursor on the left paren.
2. I set the region to (hello) and place the cursor on the left paren.

Note that in Case 1, the right paren is not part of the region while in
Case 2 it is. In the two cases above, I get exactly the same color on
the screen, then how can I distinguish between these two different
cases?

Compared to the more rational behavior of Emacs 24.3, I think the paren
which is part of the region should have the same color with the region
while the paren which is not part of the region can has matching paren
color. In this way, the user can tell which part is selected and which
part is not.



In GNU Emacs 24.3.50.1 (i686-pc-linux-gnu, GTK+ Version 3.8.7)
 of 2014-02-19 on gentoo
Windowing system distributor `The X.Org Foundation', version 11.0.11403000
Configured using:
 `configure --prefix=/usr/local/emacs/'

Important settings:
  value of $LC_COLLATE: C
  value of $LC_CTYPE: zh_CN.UTF-8
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: Messages

Minor modes in effect:
  tooltip-mode: t
  electric-indent-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
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
M-x r e p o <tab> r <tab> <return> M <backspace> s 
h o w - p a r e n - m o d e SPC a d d SPC c o n f <backspace> 
<backspace> <backspace> <backspace> <backspace> s SPC 
c o n f u s i o C-g C-h f t r a n <tab> s <backspace> 
i <tab> <return> C-x o C-n C-n C-n C-n C-n C-n C-n 
C-l C-n C-n C-n C-n C-n C-n C-l C-n C-n C-n C-n C-l 
C-n C-n C-n C-l C-n C-n C-n C-l q M-x r e C-g C-x b 
<tab> <return> M-x r e p o <tab> r <tab> <return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Making completion list...
Quit
Type C-x 1 to delete the help window, C-M-v to scroll help.
Quit
Making completion list... [2 times]

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
help-fns mail-prsvr mail-utils help-mode easymenu time-date china-util
tooltip electric uniquify ediff-hook vc-hooks lisp-float-type mwheel
x-win x-dnd tool-bar dnd fontset image regexp-opt fringe tabulated-list
newcomment lisp-mode prog-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 minibuffer nadvice loaddefs button faces cus-face macroexp
files text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
dbusbind gfilenotify dynamic-setting system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty emacs)