I tried it on gnu emacs 21 on Debian and 22 on Debian and Windows and it seems to fix the issue for me. Unfortunately I don't have a working xemacs at the moment so I can't test it there. The patch is trivial, but I'll attach it
this patch in turn broke xemacs... :)
proper fix is in the darcs repo.
;; Make sure slime-fuzzy-target-buffer-completions-mode's map is ;; before everything else. (setf minor-mode-map-alist (stable-sort minor-mode-map-alist (lambda (a b) (eq a 'slime-fuzzy-target-buffer-completions-mode)) :key #'car))
thanks,