Fiddling with the sensitivity setting solved this for me.
For me the touchpad works quite well after adjusting the parameters, but for lengthy work with multiple windows on the desktop I personally prefer a high quality mouse. I have adapted a script written by Mark H. Harris to allow to turn the internal touchpad off completely until the next boot. This script could be put on any keyboard key combination if used very often.
See in the tools folder at github.com/rricharz/pi-top-setup
I'd be happy with phantom clicks at this point, two hours into owning one of these and my mouse/keyboard no longer work.