I use a Fujitsu U904 as my job’s daily driver. It’s approaching three years old and was subject to a few hand-me-downs along the way but it’s still a very capable Ultrabook and with the QWUXGA touch screens its perfect for onsite visits.
One remnant of its hard life was the temperamental touchpad, that would work on a level flat surface but moving it to a lap or similar and the “pinch to zoom” would kick in when trying to move the mouse.
Usual troubleshooting commenced with the latest drivers being installed, as this issue co-incised with a fresh install of Windows 10. Suspecting a grounding issue of the capacitive touchpad, off came the underside cover and checked to see any missing covers/captain tape that could have caused a short, without success.