I have a new laptop with an "ETPS/2 Elantech Touchpad".

A single finger is only detected, if it is held in such a way that a big area touches the pad. If one touches the pad only with the fingertip, it wil not be detected, both for clicking and for moving the pointer.

Strangley, two-finger gestures are detected even if the pad is only touched with the fingertips.

On ubuntuusers.de I found that Elantech touchpads require to reload the psmouse-module by:

sudo modprobe -r psmouse
sudo modprobe psmouse proto=imps 

If I do this, one finger finally gets detected as it should, but all two or more finger gestures stop working. Also

grep -B 5 mouse /proc/bus/input/devices

tells that the touchpad now is identified as a mouse, while before the changes it was identified correctly as ETPS/2 Elantech Touchpad.