bug#52130: 27.2; Wrong default key binding for `mouse-drag-set-region'

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

FWIW, I object to the default key binding of `C-M-down-mouse-1 to
`mouse-drag-region-rectangle'.

This prefix should never have been given to that command.

Why?  Because:

1. There are no other rectangular-region commands on, or that will be
   put on, the same prefix (`C-M-').

2. There are plenty of sets of related commands that it does make sense
   to put on that prefix (`C-M-').

3. `rectangle-mark-mode' is on `C-x SPC'.  This is the other rectangle
   command that involves the active region.

   And other rectangle commands that don't necessarily involve the
   active region are also on prefix key `C-x'.

   (Those other, non-active region rectangle commands are actually on
   `C-x r', but using that prefix for both rectangles and completely
   unrelated commands (e.g. bookmarks) is misguided, and I hope that mix
   will be abandoned someday.)

I don't think that binding was well thought out.  I'd like to see Emacs
instead use these default bindings, on `C-x', for such behavior:

(global-set-key [(control x) mouse-1] 'mouse-set-point)
(global-set-key [(control x) down-mouse-1] 'mouse-drag-region-rectangle)

Can we please remove the `C-M-' mouse-1 bindings default for mouse-1
rectangle definition, and replace them with `C-x' mouse-1 bindings?


In GNU Emacs 27.2 (build 1, x86_64-w64-mingw32)
 of 2021-03-26
Repository revision: deef5efafb70f4b171265b896505b92b6eef24e6
Windowing system distributor `Microsoft Corp.', version 10.0.19042
Configured using:
 `configure --without-dbus --host=x86_64-w64-mingw32
 --without-compress-install 'CFLAGS=-O2 -static''