xserver-xorg-input-synaptics package causes Elan touchpad jumpiness

[Whit Blauvelt]

On a ASUS Zenbook, UX331FA, with Ubuntu 19.10 (actually Xubutu), the pad was wildly jumpy, even responding when not directly touched, until I uninstalled this package. This is a known problem. The pad works well after the package is removed. See for instance https://askubuntu.com/questions/903379/how-do-i-disable-tap-to-click-on-the-touchpad-in-ubuntu-gnome-17-04/904677 -- which despite its title has as the top-rated suggestion this.

I don't know what the theory of operation of this package is, or why it should be inserting itself into operation when it's not a Synaptics touchpad. The bug is, when it's an Elan pad, it should not do so.