SL3 gear vs eye icon

I am just starting with SL3 and I notice that now there appears to be only a visibility "eye" on layers and not the gear icon allowing for settings on each layer. I notice that it appears the one gear at the bottom seems to work for all the layers, but I am confused by the visibility icon...and I could not find it either on new features or in the tutorials. Does it hide an entire layer or what...what is the function, please...thanks :)

3 Replies