bug#68914: Windows makes Emacs choke on and swallow the WIN keys

[Nikolay Kudryavtsev]

Hello.

I think I've seen this bug in the wild a couple of times too.

But there's something else. I'm not sure if it's the same bug, but 
something's been iffy about Emacs keyboard input handling on Windows for 
the last few major versions.

Unfortunately I've yet to find a simple reproduction recipe and hence 
why I haven't filled that one the tracker. The problem is as follows.

I use a certain piece of software that switches between keyboard layouts 
by CAPS LOCK. So CAPS LOCK, the feature, is normally mostly inactive on 
my machine and requires a certain other combination to activate. Emacs 
normally respects that. Except when it's under a load running lisp code. 
During that time there are time intervals during which pressing CAPS 
LOCK would incorrectly set it on for me.

One way I can reliably reproduce this is by doing M-x list-packages and 
then tapping CAPS LOCK. At some point it would light up.

Thus I believe that the input handling intermittently breaks during the 
high load(lisp evaluation).

My testing had shown that the last version that does not suffer from 
this is Emacs 25.

Just posting this in case it's the same problem and this information is 
of any use in debugging.