bug#54289: 29.0.50; Emacs ignores xmodmap Super_L assignment

[Stephen Berman <stephen.berman@gmx.net>]

On Tue, 08 Mar 2022 08:39:59 +0800 Po Lu <luangruo@yahoo.com> wrote:

> Po Lu <luangruo@yahoo.com> writes:
>
>> Stephen Berman <stephen.berman@gmx.net> writes:
>>
>>> I have these entries in ~/.Xmodmap:
>>>
>>> keysym Super_L = slash
>>> keysym Menu = backslash
>>>
>>> In my latest build from master (details below), the Super_L assignment
>>> is ignored and Emacs does not react at all to pressing the Super_L key
>>> (the Menu assignment is still recognized).  According to git bisect the
>>> following commit introduced this behavior change:
>>
>> Thanks, that's very odd.  Do GTK programs also ignore this mapping?

AFAIK Xfce4 uses Gtk3, and e.g. xfce4-terminal and thunar (file manager)
recognize my Super_L mapping to `/'.  LibreOffice does too.  The only
other program I use that ignores Super_L is Firefox, but it has since
long before this Emacs problem started (with your commit 15910e5d
according to git bisect); I've search the web about this Firefox issue
but haven't found anything.

> If that is so, you probably have a stray modifier bound to Super_L
> (perhaps Mod4?)
>
> In that case, you should also add:
>
>   remove Super_L = Mod4
>
> Or something of the sorts to your .Xmodmap.

The only uncommented lines im my .Xmodmap file are these:

remove Lock      = Caps_Lock
keysym Caps_Lock = Control_L
add    Control   = Control_L
keysym Super_L = slash
keysym Menu = backslash

Of these, Emacs fails to recognize only the Super_L mapping, since the
above-mentioned commit.  (As an experiment I added `remove Super_L =
Mod4' before the Super_L = slash mapping, logged out and back in, but
the result was that none of the .Xmodmap mappings were recognized, not
just in Emacs but also e.g. in xfce4-terminal.  So I removed that line
to restore the status quo ante.)

Steve Berman