studio mode

When I switch to studio mode, I can preview just one scene; the other scenes are black. In multi-view mode also just one scene shows up, the others are black. I search for such problem but I failed to find it. Would you, please, help me fix that? Thank you in advance!

I have two different scenes, each scene uses a different video source, but each source uses the same webcam "item". The first source uses the webcam with a 1.333 ratio, the second source uses the webcam with a widescreen ratio. Problem is, even if I have "Deactivate when not showing" checked on...