anchor.diff:     (%category :initarg :category :reader category)))
   
   (defun unsubscribe-notification (window category)
  -  (mezzano.supervisor:fifo-push (make-instance 'unsubscribe-event
  -                                               :window window
  -                                               :category category)
  -                                *event-queue*))
  +  (submit-compositor-event (make-instance 'unsubscribe-event
  +                                          :window window
  +                                          :category category)))
   
   (defmethod process-event ((event unsubscribe-event))
     (setf (slot-value (window event) '%subscribed-notifications)
  
positive.code:   (send-event (window event) event))
  
  (defun close-window (window)
    (mezzano.supervisor:fifo-push (make-instance 'window-close-event
                                                 :window window)
                                  *event-queue*))
  
  ;;;; Window activation changed.
  
  
negative.code:                                :buffer (mezzano.gui:make-surface width height)
                                 :layer layer
                                 :kind kind)))
      (submit-compositor-event (make-instance 'window-create-event
                                              :window window
                                              :initial-z-order (or initial-z-order :top)))
      window))
  
  ;;;; Window close event.
  