instead of binding M-backspace.
(define-key map [(meta down)] 'ido-next-work-directory)
(define-key map [backspace] 'ido-delete-backward-updir)
(define-key map "\d" 'ido-delete-backward-updir)
- (define-key map [(meta backspace)] 'ido-delete-backward-word-updir)
+ (define-key map [remap backward-kill-word] 'ido-delete-backward-word-updir) ; M-DEL
+
(define-key map [(control backspace)] 'ido-up-directory)
(define-key map "\C-l" 'ido-reread-directory)
(define-key map [(meta ?d)] 'ido-wide-find-dir-or-delete-dir)