bug#30010: 25.3; changing layout in Windows 8.1 causes endless scroll in echo-area

[Eli Zaretskii <eliz@gnu.org>]

> Date: Mon, 08 Jan 2018 10:52:48 +0100
> From: martin rudalics <rudalics@gmx.at>
> CC: kireev.artur@live.ru, 30010@debbugs.gnu.org
> 
>  >> Couldn't we tell users how to prevent Emacs from fiddling with such
>  >> key bindings?
>  >
>  > I thought about mentioning this in PROBLEMS, but it sounded too
>  > obscure even for that.  I could be convinced, though.  Did you mean
>  > PROBLEMS or did you mean something else?
> 
> It looks to me as if now on Windows (1) Emacs grasps key combinations
> before anyone else gets hold of them and (2) if it doesn't find an
> appropriate binding for them, emit a warning unless it's a combination
> reserved for Windows itself.

Are you talking about Emacs 26 or later?  This bug report is about
Emacs 25, where AFAIR the above was not true.

> For example, on XP I use ahk to emulate the Aero combination of
> 
> lwindow key + left key
> 
> via
> 
> ctrl + lwindow + alt + left key
> 
> This works with all other applications and also in a "normal" emacs
> where I assign
> 
> (setq w32-lwindow-modifier 'hyper)	; lwindow is hyper
> 
> But with emacs -Q I get the warning
> 
> <C-M-lwindow> is undefined
> 
> although I apparently don't get it in later invocations of the same
> executable.  I think (2) is a bad idea and there should be an option
> to turn off such warnings.  Unfortunately, I have not been able to
> understand how this mechanism works nowadays.

Maybe we finally have a reason to provide a user facility for
disabling the keyboard hook.  (It would have to be on master, I think,
as AFAIR it is not very trivial, but maybe I misremember, or missed
some easy way of doing that.)