anchor.diff:  (defvar *compositor-debug-enable* nil)
   
   (defvar *event-queue* (mezzano.sync:make-mailbox :name 'compositor-event-queue)
  -  "Internal FIFO used to submit events to the compositor.")
  +  "Internal mailbox used to submit events to the compositor.")
   
   (defun submit-compositor-event (event)
     (mezzano.sync:mailbox-send event *event-queue*))
  
positive.code: 
  (defun send-event (window event)
    "Send an event to a window."
    (cond ((mezzano.supervisor:fifo-push event (fifo window) nil)
           (when (window-unresponsive window)
             (expand-clip-rectangle-by-window window)
             (setf (window-unresponsive window) nil)))
  
negative.code:   ((%x :initarg :x :accessor window-x)
     (%y :initarg :y :accessor window-y)
     (%thread :initarg :thread :accessor window-thread)
     (%mailbox :initarg :mailbox :reader mailbox)
     (%buffer :initarg :buffer :reader window-buffer)
     (%layer :initarg :layer :reader layer)
     (%subscribed-notifications :initarg :notifications :reader subscribed-notifications)
  