Will set this to verified since the alert is definitely not popping up:

https://trunk-mysql.nightly.sakaiproject.org, build: 573286a7

This problem was about getting a navigation alert popup while previewing or taking an assessment.

If there's some other issue with using the "Jump to Content" during an assessment that is probably a new/different issue. 

Tested on https://trunk-mysql.nightly.sakaiproject.org, build: 573286a7

Chrome (Win10):

After clicking Preview, (on the Begin page), tabbing and hitting enter on "Jump to Content", I was taken back to the Edit quiz page.

Tabbing, clicking enter once I got to the Begin Assessment button, I was able to preview the quiz. Tabbed to Table of Contents, tabbed to the question, tabbed to answer, submitted and tabbed to Done.

Firefox v.69.0.2 (64-bit) (Win10):

After clicking Preview, (on the Begin page),  tabbing and hitting enter on "Jump to Content", nothing happens.

Tabbing to Submit for Grading after answering the question, and hitting enter on the submit for grading button just refreshes the page and removes the answer.

I was going to record a video showing the behaviors, but the second time around, both browsers behaved as expected. "Jump to Content" and tabbing, I was able to access everything and "submit" . Not sure why the first time around the behavior was a little different. 

We have this here to disable the back button from being pressed. However it looks like some (all?) browsers trigger the popstate event when an anchor is navigated to. 

Maybe it's possible to still disable the back button but allow the hashchange. I can look at this, this code is in the headscripts (disableBackButton)

https://stackoverflow.com/questions/25634422/stop-firing-popstate-on-hashchange