Comment 14 for bug 1275416

For the record, I've also noticed this (running Trusty), and the workaround mentioned by jony_kalavera (mr-jony) re-enables the touchscreen for me. I can't say right now whether or not it fixes subsequent resumes.

Also - I've noticed that it only seems to affect the panel(s) and desktop (I'm using Gnome Flashback) - chrome seems to respond as normal to touch events.