anchor.diff:  
       ;; Populate list of windows
       (loop for w in (query-tree *root*) do
  -         (when (and (eql (window-map-state w) :viewable) 
  +         (when (and (eql (window-map-state w) :viewable)
                       (eql (window-override-redirect w) :off))
              (add-window w)))
   
  
positive.code:            (rtl (rrem item tl :test test)))
        (cond ((listp hd)
               (let ((rhd (rrem item hd :test test)))
                 (if rhd 
                     (cons rhd rtl)
                     rtl)))
              ((funcall test item hd) rtl)
  
negative.code:            (next (mod (funcall way nw) n)))
        (nth next *windows*))))
  
  (defparameter *groupers* (list
                            #'(lambda (w)
                                (multiple-value-bind (name class) (get-wm-class w)
                                  (string= class "Idl"))))
    "List of predicates against which windows are grouped")
  
  