It just goes to show that uninstalling avast does not remove all of avast (I think it should - others may differ) and that your avast settings from your previous install and your tinkering with settings plagues you yet.
In each of the providers for avast in their Customized > "Advanced" tab have a checkbox for "Show detailed info on performed action".
You have probably got this checked in the Webshield ... but check all your active providers and uncheck the "Show detailed info on performed action" and the popup information should cease.