Navigation Panel add-on (the "application") is shareware. You can use the application during a test period of 15 days. Following this period, if you wish to continue to use application, you must register.
To register, visit the application homepage and process the online secure registration form. The registration fee is $23.
After that you will receive a key via e-mail (you may need to wait 2-3 days to receive a key), which you can enter in the Registration dialog ("Help -- Register" menu command).