Certainly not a feature and I don't know if it could be called a feature as that would mean it would be across all avast5 users, certainly on a given OS. This doesn't happen to me on XP Pro SP3.
Have you made any changes to the avast default settings ?
Did you install avast5 over avast4.8 or uninstall 4.8 before installing avast5 ?
Try a repair of avast. Add Remove programs, select 'avast! Anti-Virus,' click the Change/Remove button and scroll down to Repair, click next and follow.