Xorg will use /dev/input/mice, even though another pointer is configured in xorg.conf
Created attachment 9509 [details]
Created attachment 9510 [details]
you can work around this with Option "CorePointer" and Option "CoreKeyboard" in the Device section, rather than doing it in ServerLayout.
workaround pushed to master.
Created attachment 9522 [details]
Created attachment 9523 [details]
I may have misunderstood the workaround, but it doesn't seem to work
Option "CorePointer" "True"
in your InputDevice section.