What you are referring to is the "avast online security" add-on.
The AOS has proven itself to be more trouble than it's worth.
Many users either disable it in their browsers via the "tools/extension"
menu or completely uninstall it. I don't even have it installed.
To uninstall it...Control Panel>Uninstall a Program>double click "avast">click "change">untick "Browser Protection">reboot.
Doing this will not lead to any decrease in protection. The three resident shields (web, file and mail) will keep you safe.