bug#9419: 24.0.50; C-x k deletes the entire frame instead of switching to another buffer

[martin rudalics]

> - the use of save-window-excursion is normally for "I want to run this
>   code which fiddles with the windows, but I don't want it to fiddle
>   with the windows".  I.e. unless the code really only fiddles with
>   windows and never with frames it is actually a bug since you can't
>   fully undo frame operations (they're visible to the user before we
>   get to try and undo them).

My principal problem with `save-window-excursion' is that it undoes my
changes to the configuration too.  Hence, unless it remains restricted
to modal windows, I find `save-window-excursion' distracting.

> - the use of "get current-window-configuration, store it in a global var,
>   give the hand back to the user, at some later time, call
>   set-window-configuration".  This is not a good solution since it
>   assumes that the user works in a strict nesting way, whereas in
>   practice (and with frames even more so), the user may interleave two
>   or more activities, so the set-window-configuration may end up
>   deleting/resetting windows in undesired ways.

This is even worse than `save-window-excursion'.  In particular when
buffers got killed in between.

martin