anchor.diff:                 (:map-notify
                   (window override-redirect-p)
                   (unless override-redirect-p
  -                  (focus (add window))))
  -               (:destroy-notify
  +                  (focus (plus window))))
  +               (:unmap-notify
                   (window)
  -                (focus (destroy window)))))
  +                (focus (minus window)))))
         (ungrab-button *root* (code *move*) :modifiers (state *move*))
         (ungrab-button *root* (code *resize*) :modifiers (state *resize*))
         (ungrab-button *root* (code *kill*) :modifiers (state *kill*))
  
positive.code: 
  (defvar *display* (open-default-display))
  (defvar *root* (screen-root (display-default-screen *display*)))
  (defparameter *windows* nil "List of managed windows.")
  (defparameter *last* nil "Last focused window.")
  (defparameter *curr* nil "Current focused window.")
  
  
negative.code:     (loop for w in (query-tree *root*) do
           (when (and (eql (window-map-state w) :viewable)
                      (eql (window-override-redirect w) :off))
             (plus w)))
  
      (setf (window-event-mask *root*) '(:substructure-notify))
  
  