`mime-view-mode-map' instead of `mime-view-define-keymap-hook'.
[cf. <emacs-mime-ja:950>]
(when (boundp 'widget-keymap)
(set-keymap-parent (current-local-map) widget-keymap)))
-(add-hook 'mime-view-define-keymap-hook 'mime-view-maybe-inherit-widget-keymap)
+(add-hook 'mime-view-mode-hook 'mime-view-maybe-inherit-widget-keymap)
(defun mime-view-define-keymap (&optional default)
(let ((mime-view-mode-map (if (keymapp default)