In fact, you choose for it as it is not the default action of avast. If you set this option, the resident protection will inform you about the files currently being tested. The information will be displayed in the bottom right corner of the screen, right above the system tray. Oh, it's on the help file
1) Left click the 'a' blue icon on system tray
2) Choose the Standard Shield provider
3) Click on Customize
4) Go to Avanced tab
5) Uncheck 'Show detailed info on performed action'
