Interesting. This splits windows vertically.. how about horizonally?
> Later, I split windows again; but then I get`C-x 4 b' switches to another buffer (with luck, the one you want) in another
> the same buffer I've been working on in both windows: I've to switch
> buffers again to see the two buffers I was working on in the
> first place.
>
> This is a bit annoying. Is it possible to have the buffer
> in the new window, that has been there before?
window.