Thank you, Andreas Roehler, for your answer:
Hmm, when it is about to restore some older windows configuration,
previous-buffer and the like will not do it, as being volatile.
You could use result of (current-window-configuration) similar to
registered positions as shown.
Then (set-window-configuration MY-last-window-configuration), now
jumping to subsequent stores.
Actually, the intention is not to alter the windows configuration at all,
but to change the buffer that one of the windows shows. The latter should be
done by a keystroke that cycles through the whole list of buffers.
This can nearly be achieved by binding the command previous-buffer so some
suitable key. But this is not the complete solution, since previous-buffer
typically cycles through just some of the buffers, not all of them.
So it would be great if somebody would know of a command that does that or if
somebody could outline a way to configure, alter, or advice the command
previous-buffer to include all the buffers in its scope.
Juergen