bug#34014: 25.2; binding down mouse event with modifier to mouse-drag-region does not work

[Adolf Mathias]

======================

>From 'emacs -Q' under X11, Ubuntu Bionic Beaver, enter:
M-: (define-key global-map '[S-down-mouse-1] 'mouse-drag-region)

Now attempting to drag a region with held down shift key gives the
error message:

<S-drag-mouse-1> is undefined

Redefining the mouse key without shift modifier, and then dragging,
works as intended:
M-: (define-key global-map '[down-mouse-1] 'mouse-drag-region)

This used to work in Emacs 24 and before.

======================



In GNU Emacs 25.2.2 (x86_64-pc-linux-gnu, GTK+ Version 3.22.21)
 of 2017-09-22, modified by Debian built on lgw01-amd64-050
Windowing system distributor 'The X.Org Foundation', version 11.0.11906000
System Description:    Ubuntu 18.04.1 LTS

Configured using:
 'configure --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/lib
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes
 
--enable-locallisppath=/etc/emacs25:/etc/emacs:/usr/local/share/emacs/25.2/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/25.2/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --without-gconf --build x86_64-linux-gnu
 --prefix=/usr --sharedstatedir=/var/lib --libexecdir=/usr/lib
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes
 
--enable-locallisppath=/etc/emacs25:/etc/emacs:/usr/local/share/emacs/25.2/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/25.2/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --without-gconf --with-x=yes --with-x-toolkit=gtk3
 --with-toolkit-scroll-bars 'CFLAGS=-g -O2
 -fdebug-prefix-map=/build/emacs25-jYekUr/emacs25-25.2+1=.
-fstack-protector-strong
 -Wformat -Werror=format-security -Wall' 'CPPFLAGS=-Wdate-time
 -D_FORTIFY_SOURCE=2' 'LDFLAGS=-Wl,-Bsymbolic-functions -Wl,-z,relro''

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GSETTINGS NOTIFY
ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11

Important settings:
  value of $LC_CTYPE: en_US.utf8
  value of $LC_MONETARY: de_DE.UTF-8
  value of $LC_NUMERIC: C
  value of $LC_TIME: C
  value of $LANG: C
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-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
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
Loading /etc/emacs/site-start.d/50dictionaries-common.el (source)...done
For information about GNU Emacs and the GNU system, type C-h C-a.
gui-get-primary-selection: No selection is available
Mark set
mouse-drag-region
Mark set
mouse-drag-region
Mark set
<S-drag-mouse-1> is undefined
C-c RET is undefined

Load-path shadows:
/usr/share/emacs/25.2/site-lisp/debian-startup hides
/usr/share/emacs/site-lisp/debian-startup
/usr/share/emacs25/site-lisp/cmake-data/cmake-mode hides
/usr/share/emacs/site-lisp/cmake-mode
/usr/share/emacs25/site-lisp/auctex/context-nl hides
/usr/share/emacs/site-lisp/auctex/context-nl
/usr/share/emacs25/site-lisp/auctex/tex hides
/usr/share/emacs/site-lisp/auctex/tex
/usr/share/emacs25/site-lisp/auctex/tex-style hides
/usr/share/emacs/site-lisp/auctex/tex-style
/usr/share/emacs25/site-lisp/auctex/latex hides
/usr/share/emacs/site-lisp/auctex/latex
/usr/share/emacs25/site-lisp/auctex/tex-font hides
/usr/share/emacs/site-lisp/auctex/tex-font
/usr/share/emacs25/site-lisp/auctex/context-en hides
/usr/share/emacs/site-lisp/auctex/context-en
/usr/share/emacs25/site-lisp/auctex/tex-ispell hides
/usr/share/emacs/site-lisp/auctex/tex-ispell
/usr/share/emacs25/site-lisp/auctex/font-latex hides
/usr/share/emacs/site-lisp/auctex/font-latex
/usr/share/emacs25/site-lisp/auctex/texmathp hides
/usr/share/emacs/site-lisp/auctex/texmathp
/usr/share/emacs25/site-lisp/auctex/toolbar-x hides
/usr/share/emacs/site-lisp/auctex/toolbar-x
/usr/share/emacs25/site-lisp/auctex/multi-prompt hides
/usr/share/emacs/site-lisp/auctex/multi-prompt
/usr/share/emacs25/site-lisp/auctex/context hides
/usr/share/emacs/site-lisp/auctex/context
/usr/share/emacs25/site-lisp/auctex/tex-jp hides
/usr/share/emacs/site-lisp/auctex/tex-jp
/usr/share/emacs25/site-lisp/auctex/preview hides
/usr/share/emacs/site-lisp/auctex/preview
/usr/share/emacs25/site-lisp/auctex/prv-emacs hides
/usr/share/emacs/site-lisp/auctex/prv-emacs
/usr/share/emacs25/site-lisp/auctex/tex-info hides
/usr/share/emacs/site-lisp/auctex/tex-info
/usr/share/emacs25/site-lisp/auctex/tex-fold hides
/usr/share/emacs/site-lisp/auctex/tex-fold
/usr/share/emacs25/site-lisp/auctex/bib-cite hides
/usr/share/emacs/site-lisp/auctex/bib-cite
/usr/share/emacs25/site-lisp/auctex/tex-mik hides
/usr/share/emacs/site-lisp/auctex/tex-mik
/usr/share/emacs25/site-lisp/auctex/tex-buf hides
/usr/share/emacs/site-lisp/auctex/tex-buf
/usr/share/emacs25/site-lisp/auctex/tex-bar hides
/usr/share/emacs/site-lisp/auctex/tex-bar
/usr/share/emacs25/site-lisp/auctex/plain-tex hides
/usr/share/emacs/site-lisp/auctex/plain-tex

Features:
(shadow sort mail-extr emacsbug message dired format-spec rfc822 mml
mml-sec password-cache epg epg-config gnus-util mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util help-fns help-mode easymenu
cl-loaddefs pcase cl-lib mail-prsvr mail-utils preview-latex tex-site
auto-loads time-date mule-util tooltip eldoc electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel x-win term/common-win x-dnd
tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment
elisp-mode lisp-mode prog-mode register page menu-bar rfn-eshadow timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
frame cl-generic cham georgian utf-8-lang misc-lang vietnamese tibetan
thai tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek romanian
slovak czech european ethiopic indian cyrillic chinese charscript
case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer
cl-preloaded 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 dbusbind inotify
dynamic-setting system-font-setting font-render-setting move-toolbar gtk
x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 91833 8234)
 (symbols 48 20167 0)
 (miscs 40 103 171)
 (strings 32 15355 5105)
 (string-bytes 1 440851)
 (vectors 16 11880)
 (vector-slots 8 434204 5146)
 (floats 8 164 159)
 (intervals 56 301 0)
 (buffers 976 19))