WOW, 9 years this discussion has been going on and still no changes! :(
I came here also looking for a solution as I have built a progress bar with buttons that become active for the learner when they reach each section of the course, but if the learner clicks on one of the buttons to jump to a previous section, then presses the back button, they are taken back to where they were, not the numerically linear previous slide.
Please give us the CHOICE by adding a new trigger behaviour. I'd be more than happy to create 2 buttons in my Nav for the learners (one for previous and one for last visited).