anchor.diff:            (let ((y0 (+ sy0 (* index item-height)))
                   (y1 (+ sy0 (* (1+ index) item-height))))
               (multiple-value-bind (background foreground)
  -                (if (if (list-pane-exclusive-p pane)
  +                (cond ((not (slot-boundp pane 'value))
  +                       (values (pane-background pane) (pane-foreground pane)))
  +                      ((if (list-pane-exclusive-p pane)
                           (funcall (list-pane-test pane)
                                    (elt (generic-list-pane-item-values pane) index)
                                    (gadget-value pane))
                           (member (elt (generic-list-pane-item-values pane) index) (gadget-value pane)
                                   :test (list-pane-test pane)))
  -                    (values highlight-ink (pane-background pane))
  -                    (values (pane-background pane) (pane-foreground pane)))
  +                       (values highlight-ink (pane-background pane)))
  +                      (t (values (pane-background pane) (pane-foreground pane))))
                 (draw-rectangle* pane rx0 y0 rx1 y1 :filled t :ink background)
                 (draw-text* pane (elt (generic-list-pane-item-strings pane) index)
                             sx0
  
positive.code:                                  (< (/ (- now last-click-time) internal-time-units-per-second) *double-click-delay*))
                         (setf last-click-time now))))
                   (end-it ()
                     (unless all-done
                       (setf all-done t)
                       (throw 'popup-list-box-done nil))))
            
            (catch 'popup-list-box-done
              (setf (slot-value list-pane 'value-changed-callback)
                    (lambda (pane value)
                      (declare (ignore pane value))
                      (when ready-to-exit (end-it))))
              
              (tracking-pointer (list-pane :multiple-window t :highlight nil)
                (:pointer-motion (&key event window x y)
                   (cond (inner-grab (handle-event inner-grab (rewrite-event-for-grab inner-grab event)))
  
negative.code: 
  ;; - Should RADIO-BOX-PANE and CHECK-BOX-PANE use rack or box layout?
  
  ;; - :CHOICES initarg to RADIO-BOX and CHECK-BOX is from Franz' user
  ;;   guide.
  
  