Most of the current day antiviruses have a context menu option for the folders like ‘Scan with <AV Name>’. Even whilst a scan is in progress normally this menu option is not disturbed. However I just observed in the recent installation of Spyware Doctor that during a scan even this menu is updated to reflect its current state.
See snapshot below:
This is a way bit advantageous because even inadvertently you can not choose this option which might enqueue another unwarranted scanning job on the AV engine besides slowing down the PC performance.
Let us hope that other AV vendors emulate this in their products too.