I suppose it is the subtle distinction between a screen (which IoT does have) and the concept of multiple screens only one of which is front (which IoT does NOT have). It can switch to another screen of course but they don't exists until that app runs.
You can always capture your own screen (if you construct it so that you can anyway) but there is no methodology to 'see' anyone else's screen as it isn't there.
ricl : F/gamma = ma : Law ii(a) : https://climatedatablog.wordpress.com/2016/01/02/an-energy-challenge-2016/ #AnEnergyChallenge2016
I see people saying you can't use Microsoft RDC to remote desktop into Pi/Raspbian. I use a quite old version of Microsoft RDC to connect to my Pi all the time, I don't get sound but not an issue for me. It connects to an xrdp server on the Pi.
There is the Windows IoT Remote Client that allows you to see/use the Pi "desktop" via your Windows PC (over ethernet link). Works well with the last stable build 15063 - but no joy with the latest Insider Program builds (MS broke it).