> An alternative would be to make C-x b use another window in such a case.
 > I.e. remove the `force-same-window' argument (I think that would make
 > sense at least for the window-minibuffer-p case).

Agreed.

 > An other alternative
 > would be to un-dedicate the window (only after prompting the user, tho).

Patch attached.  In the *log-edit-files* case we could additionally make
the window weakly dedicated in order to avoid this problem all together.

martin