anchor.diff:    (with-slots (frame-manager submenu-frame) sub-menu
       (when submenu-frame
         (mapc #'destroy-substructure (menu-children sub-menu))
  -      (mapc #'(lambda (child)
  -		(setf (slot-value child 'destroyed) t))
  -	    (menu-children sub-menu))
         (disown-frame frame-manager submenu-frame)
         (setf submenu-frame nil))))
   
   (defmethod arm-branch ((sub-menu menu-button-submenu-pane))
  -  (unless (slot-value sub-menu 'destroyed)
  -    (with-slots (client frame-manager submenu-frame) sub-menu
  -      (arm-menu client)
  -      (if submenu-frame
  -	  (progn (mapc #'destroy-substructure (menu-children sub-menu))
  -		 (mapc #'disarm-menu (menu-children sub-menu)))
  -	  (progn
  -	    (mapc #'destroy-substructure (menu-children client))
  -	    (create-substructure sub-menu sub-menu)))
  -      (arm-menu sub-menu))))
  +  (with-slots (client frame-manager submenu-frame) sub-menu
  +    (arm-menu client)
  +    (if submenu-frame
  +	(progn (mapc #'destroy-substructure (menu-children sub-menu))
  +	       (mapc #'disarm-menu (menu-children sub-menu)))
  +	(progn
  +	  (mapc #'destroy-substructure (menu-children client))
  +	  (create-substructure sub-menu sub-menu)))
  +    (arm-menu sub-menu)))
   	      
   (defmethod handle-event ((pane menu-button-submenu-pane) (event pointer-button-release-event))
     (destroy-substructure (menu-root pane)))
  
positive.code:       (destroy-substructure (menu-root pane)))))
  
  (defmethod handle-event ((pane menu-button-leaf-pane) (event pointer-exit-event))
    (unless (slot-value pane 'destroyed)
      (disarm-menu pane)))
  
  (defmethod handle-event ((pane menu-button-leaf-pane) (event pointer-ungrab-event))
    (destroy-substructure (menu-root pane)))
  
negative.code:   ((command :initform nil :initarg :command)))
  
  (defmethod arm-branch ((button menu-button-leaf-pane))
    (with-slots (client) button
      (arm-menu client)
      (mapc #'destroy-substructure (menu-children client))
      (arm-menu button)))
  
  (defmethod destroy-substructure ((button menu-button-leaf-pane))
    (with-slots (armed) button
        (setf armed nil)))
  
  (defmethod handle-event ((pane menu-button-leaf-pane) (event pointer-button-release-event))
  