bug#31415: 27.0.50; Strange behavior on Command-$ in MacOS

[Eli Zaretskii]

> Date: Sun, 13 May 2018 11:28:10 +0100
> From: Alan Third <alan@idiocy.org>
> Cc: 31415@debbugs.gnu.org
> 
> On Thu, May 10, 2018 at 06:30:33PM -0700, John Mastro wrote:
> > By default, the "command" key in MacOS is bound to "super". If I type
> > s-$, Emacs seems to wait for input that it never receives. Anything I
> > type afterward appears to be ignored, except `ESC ESC ESC', which gets
> > Emacs out of this state. However, even hitting `C-g' repeatedly does
> > not.
> > 
> > The issue seems to be related to the command key rather than to "super"
> > or to the command bound to the key. In my configuration, I map command
> > to meta, and the same problem happens when I use M-$ to `ispell-word'.
> > 
> > Using `M-$' with command as meta worked until relatively recently. It
> > would be great if it could be brought back or made to fail more
> > explicitly.
> 
> Hmm, what’s happening is that macOS is going into a screenshot mode.
> You can see the shortcuts in system preferences ‐> keyboard ‐>
> shortcuts. I don’t know why you’ve not seen this before as I think
> it’s been the default in macOS for quite a while now.
> 
> I don’t know if we can over‐ride this, and I don’t know that we’d want
> to. 

If this cannot (or shouldn't) be fixed, how about mentioning it in the
manual?