see syndaemon -K and the recent patch discussion here: https://lists.freedesktop.org/archives/xorg-devel/2016-August/050538.html this should be used by default in libinput, over the current syndaemon -k behaviour.
https://lists.freedesktop.org/archives/wayland-devel/2016-August/030336.html
commit 1ea9fbfd4c55a28db1227b65cfa036aec5d37ef3 Author: Peter Hutterer <peter.hutterer@who-t.net> Date: Thu Aug 4 10:43:25 2016 +1000 touchpad: ignore modifier key combos for dwt
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