I've just upgraded libinput10 to 1.3.0-2 (from 1.3.0-1, which wasn't working), pulling in libinput-bin and the associated udev rules. This has fixed middle button emulation for me on my E7420 with ALPS Glidepoint.
J. -- Revd Jonathan McDowell, ULC | If they can't take a joke....fuck 'em.
