bug#16678: 24.3.50; REGRESSION: text selection is broken in Customize edit fields

[Drew Adams <drew.adams@oracle.com>]

emacs -Q

(defcustom foo '([next]) "" :type '(repeat sexp) :group 'edit)

M-x customize-option foo

In the edit field, try to select the current value, which is `[next]'.

Try to select it by dragging the mouse from start (left) to end (right).
As soon as the mouse passes the last char, to select it too, the
selection highlight disappears.

Try to select it using the keyboard to define the region: Put the cursor
before the `[' and hit `C-SPC'.  Then use `C-e' to move the cursor past
the `]'.  No region highlighting.  Try again, this time using `C-f' to
advance across the text.  As soon as you move past the `]', the region
highlighting disappears.

Users should have highlighting that shows them what text is selected -
all of that text, including the last character.  This is a regression
from Emacs 24.3, where selection worked normally.


In GNU Emacs 24.3.50.1 (i686-pc-mingw32)
 of 2014-02-02 on ODIEONE
Bzr revision: 116242 rudalics@gmx.at-20140202130041-n967dw77nw7ztvy9
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --prefix=/c/Devel/emacs/binary --enable-checking=yes,glyphs
 'CFLAGS=-O0 -g3' LDFLAGS=-Lc:/Devel/emacs/lib
 CPPFLAGS=-Ic:/Devel/emacs/include'