So i just got the program myself, and as it would seem i am having the seem problem. I've used alot of streaming programs in my days and i figured out what it is. It's not us from what it would seem but OBS itself. I don't know why it doesn't work with an internet browser, but as long as you have one opened it will (from what it seems) no matter what black screen/ mouse trail. So in other words you have to rely on the OBS program itself (or from what region you are showing through the program) is streaming fine. I don't know if Duo screening has the same problem, but if you are unsure if your stream is working or looking okay, ask friend use a different computer (sadly) or be a gambler and hope its working fine. Hope this helps you out explain the problem from what I'm exping. good luck streaming!