Dear Maintainer,

The stuck shift key was reported upstream years ago.
Apple's fork of xephyr fixed this years ago.
Once the shift key is stuck, one must close and restart
Xephyr (and of course everything running in it) to recover.

Can you please try to backport Apple's fix?

Thanks

possibly related bug:
debian-bugs-dist - Bug#531302: caps lock becomes stuck
        Package: xserver-xephyr
...
After using the caps lock key a few times, I get stuck in caps mode

# ^ please note that it looks like caps lock is stuck, but
it DOES happen even if you never touch caps lock.

possibly related bug:
 stuck alt/ctrl keys after running Xephyr, long standing issues are involved. work around is to disable compiz for now.
        wiki.edubuntu.org/Grantbow/AcerAspire4810TZ

# I am running compiz version 0.8.4-5.2

Apple's patch:
  Darwin: Trap Deactivate messages and release modifiers to avoid "stuck shift lock" (etc) bugs
http://lists.freedesktop.org/archives/xorg-announce/2008-March/000458.html

commit 606a8dc73d91a198d72d249934dc027a23f4c338
Author: Ben Byer <bbyer@bbyer.local>
Date:   Wed Oct 31 03:39:47 2007 -0700

    Darwin: Trap Deactivate messages and release modifiers to avoid "stuck shift lock" (etc) bugs
    (cherry picked from commit 2b189a99330eb465fa0d17020fb1db1e38829151)
http://www.opensource.apple.com/source/X11server/X11server-85/kdrive/xorg-server-1.6.0/ChangeLog

Shift key is also getting stuck regularly running under LXDE/metacity.

Apple's patch affects Xdarwin, which is only built/used on MacOS.

Cheers,
Julien