Tested it out last night on my Lumia 920... didn't work. Found out later that the 920 is not supported.
So... tried with my Dell Venue 8 Pro. Screen connected and "a" desktop was displayed. I say "a" desktop was displayed because it was not the same as the desktop on my tablet. It had an entirely different background... strange. It was also unresponsive... if I opened something on my tablet, it would not display on the TV (mirrored image). The mirrored image just sat at the desktop and did nothing.
Also it put my tablet display into portrait mode and would not rotate back to landscape until I disconnected.
I am going to try and do some more testing tonight!
10-08-2014 01:24 PM