Hi kuyaya,
yes, a "half" idea I would have it: Virtual Box has nothing to do with it, in my opinion the latest versions of Windows 10 need to "see" at least 2 network interfaces in the system, in addition to the one connected to the internet, to to be able to make the drop-down menu box appear. If there is only one network interface, the choice does not arise, it is unambiguous, obligatory towards that only available interface, in the sense that it is not possible to choose others. If instead there are at least 2 network interfaces, then the system offers you the possibility to choose either one or the other interface. If my thesis is correct, if on the PC where ICS has always worked, you uninstall one of the 2 network interfaces, Ethernet Realtek PCIe or the one related to Vrtual Box, keeping only one active, probably also on that PC you will not see the menu descent.