Something I just encountered - when I do a cell operation in a view, that has been duplicated from another one, this affects the first view.
E.g. I load a single unit cell of silicon, clone the view and create a 2x2x2 supercell, I suddenly have the same 2x2x2 supercell in the first view.
That's the way it's supposed to work. Having multiple views just lets you see different viewpoints.