But you don’t say what these add-ons were (as was asked), how could we possibly do any investigation into why they might have been removed.

Personally I don’t install the browser cleanup or any other cleanup component. I take responsibility for anything installed on my system or my browser.

As far as on-demand scans go - With a resident (on-access) scanner the need for on-demand scans is much depreciated. For the most part dormant/inert files are being scanned, the other active files are going to be scanned by the resident shields when they are activated.