BIgscreen wont stream 2D Desktop

[Glen]

I have a problem with trying to get desktop streaming to the large screen in each environment.

it works great for other things, i can watch TV and movies, i can use the videoplayer to play my own local content etc. But when i try to stream my desktop monitor; nothing, black screen.
However when i pull up a personal window i can see it's streaming just fine ( yes i have main screen enabled in settings)
Even stranger if i switch the main screen to "3D SBS" or "3D OU" the large screen displays a picture (albeit a messed up one because my source is not 3D)

as a test i ran VLC on my desktop with a SBS 3D movie and streamed that to bigscreen and it plays great in 3D mode. Switch it back to 2D within bigscreen and it's just black. Disable it completely and the screen reverts to the bigscreen logo.

So i should point out that this only happens when using Bigscreen downloaded from Oculus. BIgscreen from Steam seems to work just fine streaming my desktop content.
So why am i posting this in a Steam Forum? The Oculus forums seem very underutilised and the bigscreen devs seem very active here so it seemed the best way of reaching out either to them or much larger userbase that may have some ideas.
Also you will ask, "why not just switch to the bigscreen Steam version if that works ?" well this is Steam related. i want to stream some game content from my desktop to the virtual room screen and that game happens to be in Steam too. So when i run it up, it drops me out of BIgscreen and into a virtual theatre to play the game. so no one else can see it.
i just want to stream the game to the bigscreen primary monitor.

So the only way i could think of doing it was to run the Oculus version of Bigscreen and have that stream the "2D" steam game to my virtual room.

any help or ideas gratefully received.

( Oh and i checked, the build numbers of both versions are the same: 0.107.0.498c they both just updated today and the same problem occurred in the previous versions i had)


<edit> UPDATE.
The problem seems to be with virtual desktop. Ditching that and going back to a link Cable ( i'm on Oculus quest) both versions of Bigscreen beta stream to the desktop fine
I am really puzzled as to why it has an issue in one but not the other though you'd think it would be all or nothing. Like when going through "Oculus VR" instead of "SteamVR" personal" screens still work but the main screen in the room does not. or why the main screen starts working when you switch to it from 2D to 3D.

Why didn't i just use the native Quest version of Bigscreen in the first place and connect to the desktop mode on the PC ?
Just trying to avoid the inconvenience copying and typing in connect codes on a machine that is in another room and that change each time, and also running the PCVR version gives instant access to all my PC local files and network shares from the movie player in Bigscreen, which recognises a good variety of movie file formats.
With "Local files" on my Quest there's a very limited amount of storage space to put movies on and although it does DLNA, i always find it sucks.

<Edit> Update 2
OK i have sorted this. By going "My Room" > "About my Room" > "Tools and toys" and selecting "Stream Cam" then the main screen kicks into life (without changing anything and despite "show desktop feed" already being ticked there)
This step is only needed when launching Bigscreen through OculusVR AND using Virtual desktop. Bigcreen through OculusVrRworks fine on a link cable and Bigscreen launched through SteamVR works fine on both Cable and Virtual Desktop.
There's a puzzle for the devs to mull over ;-)

[Sexy Jesus]

Does not fix the issue for me. "Stream Cam" does make the big screen work, but I just see an infinite amount of what I see through my headset on it. No desktop, just the room, over and over.