Is there a way to disable the Exit button until a link is clicked?

The attached file shows a potential solution.

The Exit tab in the Player has a condition that checks whether the link on this slide has been clicked. That is tracked via a True/False variable that is changed to True when the link is clicked.

• If the variable = True, clicking Exit closes the course.
• If the variable = False, clicking Exit lightboxes a warning message. 
  • Storyline doesn't have a Disabled state for Player tabs. So I think it'd be best to show a message about why the Exit button isn't closing the course. 

Of course, there's no way to prevent the user from simply closing the course by closing browser window...