keymaps that are active in the minibuffer are described below under
"New keymaps for typing file names".
+If you want the old behavior back, put these two key bindings to your
+~/.emacs init file:
+
+ (define-key minibuffer-local-filename-completion-map
+ " " 'minibuffer-complete-word)
+ (define-key minibuffer-local-must-match-filename-map
+ " " 'minibuffer-complete-word)
+
** The completion commands TAB, SPC and ? in the minibuffer apply only
to the text before point. If there is text in the buffer after point,
it remains unchanged.