You can disable AOS from your browser menu, it is not really needed and you are still protected via the Web Shield.
to be precise - you can't use the Avast Online menu itself - go to the browser's "Add-ons" menu and disable the plug-in.
** I'm a new user to Avast, just been recommended, and the PC-based sniffing seems excellent, but the prowser experience has to hold a record for Worst Experience Ever!
On Slashdot.org, the hover rectangle comes when I go anywhere near the ticks, and the damned ticks themselves are scattered unremovably across the page, next to every link.
I shall continue to rely on NoScript, which I have come to trust, and leave Avast to cope with downloads.