Where do I turn route highlighting on / off in Google maps?

How can I show / hide the blue line representing the current route in Google Maps route planning and navigation screens? Essentially I want to toggle between the two views below: Background: I somehow managed to switch route highlighting off and now I want it back. It doesn't seem to be a bug in Google Maps, at least a phone restart doesn't restore the highlighting. I know I can just wipe Google Maps user data, but I prefer to learn how to do it properly.