For me, this was caused by my custom .desktop file. I downloaded
Firefox, unpacked it to my home and created a .desktop file for it in
~/.local/share/applicaitons as so:
#!/usr/bin/env xdg-open
[Desktop Entry]
Version=1.0
Type=Application
Terminal=false
Icon[en_US]=firefox
For anyone dealing with this issue on a Dell XPS 13 with a touchscreen
on Ubuntu 16.04, it seems to re-enabling the touch screen in the laptop
bios resolved it for me. I usually keep the touch screen disabled but
there must have been a regression in one of the kernel updates that I
got that made
