WPF - Transparency - Stream Desktop Content
I had same issue with Transparency in WPF. When you set transparency to zero, it doesn't have anything to pick up. Set it to the minimum value, then streaming software will be able to pick it up.
Just an idea, but what if you make it only almost transparent (i.e. alpha = 0.01 or so)? Then it shoud have enough "substance" to be picked up by the streaming, but still be invisible enough to not disturb the view.
One possibility is that the alpha-blending is being done totally on the GPU, preventing the streaming software from finding it. So you might try forcing software rendering in your WPF app. You can do that by setting:
RenderOptions.ProcessRenderMode = RenderMode.SoftwareOnly