There was some convoluted method requiring opening non modal window with spaceship dials that would let you audition certain bars. I believe essentially what it did was it rendered or ghost loaded piece of chord sheet and sort of auditioned segment. I hope we never go that ancient route again.

The one and only true solution, without loading "ghost" project and retaining original would be a clean Undo + history, so you could potentially go back 20 steps or more without risking of losing anything.

Less flexible solution would be a button in MTP to save snapshot of the project before browsing styles with "Audition Chord Sheet" and not demo checked. In this scenario, user would press that button before browsing styles, it would still place tracks and other data in the project, but if nothing better is found, user would be able to revert to original snapshot with single click.