anchor.diff:      (loop for w in (query-tree *root*) do
            (when (and (eql (window-map-state w) :viewable)
                       (eql (window-override-redirect w) :off))
  -           (add-window w)))
  +           (add w)))
   
       (setf (window-event-mask *root*) '(:substructure-notify))
   
  
positive.code:                                 (string= class "Idl"))))
    "List of predicates against which windows are grouped")
  
  (defun add-window (window)
    "Add window to the list of managed windows. Take care of grouping
  and don't add window already in the list."
    (let ((grouper (find-if #'(lambda (f) (funcall f window)) *groupers*)))
  
negative.code:                (:map-notify
                  (window override-redirect-p)
                  (unless override-redirect-p
                    (focus (add window))))
                 (:destroy-notify
                  (window)
                  (when (member window *windows* :test #'win=)
  