Having trouble locking an inbuilt menu
I am trying to setup up an inbuilt menu within a course that users must work through in order. Users cannot click the next topic in the menu until all slides within the previous topic have been viewed. I have managed to set up the topics headings to restrict users from clicking on the next topic but it is not working as i want it to. Currently, if a user clicks a topic and then clicks the previous button to go back to the menu slide the topic is flagged as completed and the next topic heading is made available. I need the users to click through all slides in a topic before this happens.
I have attached an example. Any help, suggestions would be great!