>On my system it's controlled by Settings...System...Multitasking...Snap windows. If enabled, maximized windows can be dragged. If disabled, they cannot. (tested only with Firefox)

Typical of M$. If you tied me to a chair, shone bright light to my face etc, I still wouldn't be able to find that. Why would it be in multitasking?

The same lack of general logic applies to things in american supermarkets. Some things are in quite unlikely places. Like lunch bags - they aren't with other paper stuff, not with other bags, but with party supplies (!).