I seem to remember a bit of functionality in one of the student/demo packages (Maya maybe). Where you could have a layer be visible, but not be able to select anything on it. So, you could work on layer 2, while referencing geometry on layer 1 without having wory about inadvertently change something on layer 1.
However I can imagine how this kind of “feature” will generate countless messages on Blender General saying: “Cannot select my objects anymore. Anybody can help me ?”
Thanks…and I must say that I have never noticed the scene selector, or if I did, didn’t pay any attention to it. It’s just amazing what you can learn on these forums…and how quickly.