It sometimes happens that you're drawing a route in the Route Creator, spent some time on this already but then you accidentally close the browser tab or go to another page or whatever. In such situation all your unsaved work is lost.
It would be nice if when in the Route Creator, page would ask you for confirmation if you really want to leave it and loose unsaved work. It works like this on many websites such as GMail. This is very easy to implement using JS browser APIs.