green box shaped thing

Is the green box which says " this web site is safe" in firefox that keeps trying to get under the mouse pointer anything to do with avast ? Can I make it go away ?

avast! Online Security is a web browser protection plugin for Google Chrome, Mozilla Firefox, Safari and Internet Explorer that combines WebRep (reputation rating system for visited websites), Site Correct (automatic correction of mistyped web URLs), Antiphishing (protection from phishing scams) and "Do not Track" features (prevention of third-party sites tracking your web browsing activity) to let you browse the web safely and securely.

http://www.avast.com/en-eu/faq.php?article=AVKB89#idt_01

yes that is a good thing but chasing the mouse pointer is pointless and annoying