Avast people have done all that work to make Online Security into a useful utility but the user is prevented by the UI from changing or verifying settings. The part of the UI window which must be clicked if the settings are to be accessed is somewhere south of the task bar, probably under the display screen lower horizontal bezel. It's out of reach.
Plenty of laptop display screens have a height of 768 pixels, my Sony VAIO for example. It's a de facto standard. Since I am unable to manage Avast Online Security on IE11, I have no choice but to disable it which is a shame because it has desirable features.