Put a 'License' topic in your 'Help' or 'About' menu.

After entering the pin code, I've got no clue wether the registration was successful or not, wether I've got a licensed program or just the trial version. Thanks. And btw, I love the name 'Giotto', makes me think of something fun and playful. Only the 'Vectorian' part bothers me a little. These two names don't seem to belong together. And another idea: make some help files that don't require being online in order to use the program.