After a while of repeated trouble with the combination USB-mouse and Synaptics touchpad on my old Dell Latitude laptop a solution was finally reached.
The problem manifested itself as either mouse cursor drifting towards top right or bottom left corner, or cursor just staying in either corner.
To solve enter…
sudo modprobe -r psmouse sudo modprobe psmouse proto=imps
…and make it permanent add last line to /etc/modprobe.d/options