I started getting the following error in Firefox only and on touchscreen only:
"ReferenceError: g is not defined".
all pointing to a FLEXSLIDER. I' unable to open assignment submissions because of that error. Note again that oddly, this only happens on Windows tablet using Firefox. Tried to clean the cache, restart, nothing helped.
Started today when I was checking submissions, suddenly I couldn't click on the '+' to list assignment submissions.
Ok, I found the fix.
cause
Firefox has the Responsive Design View as part of Developer Tools. It features touch gesture simulation using the mouse. When this has been used, Firefox enables touch events, but for some reason it doesn't always turn these back off after disabling it.
solution
Go to about:config, search for setting dom.w3c_touch_events.enabled and put it back to 0 if not already there.
This fixed it. Not sure if the flexslider javascript needs an update or it's purely Firefox issue, perhaps WPLMS team should look at it.
Thanx for sharing this information with us. We will look into this.