bug#1806: dired-pop-to-buffer in wrong place

[martin rudalics]

> Why would it override it?  It would of course bind
> split-window-preferred-function to a function that selects the right
> window and then calls the previous value.

Maybe you can come up with some advanced technique to do that but here I
would have to define a variable to save the current (user provided)
`split-window-preferred-function' and call the function I save there
within the body of the function provided by dired.  Hence an extra
variable would be needed anyway and I suppose it's easier to define that
in window.el rather than in all packages that want to change the window
to split (IIRC Calendar was one of these).

martin