I have this problem on my Dell XPS 15 9560 running Ubuntu 17.04. It occurs specifically when I am moving the pointer with one finger and I click with another finger before lifting my original finger. The only workaround is to only have one finger on the touchpad at a time, which is very slow-going. Replacing xserver-xorg-input-synaptics with xserver-xorg-input-libinput as suggested results in my keyboard not working and does not even seem to fix the problem.
I have this problem on my Dell XPS 15 9560 running Ubuntu 17.04. It occurs specifically when I am moving the pointer with one finger and I click with another finger before lifting my original finger. The only workaround is to only have one finger on the touchpad at a time, which is very slow-going. Replacing xserver- xorg-input- synaptics with xserver- xorg-input- libinput as suggested results in my keyboard not working and does not even seem to fix the problem.