anchor.diff:    (let* ((style (ensure-style style))
            (border-size (if (style-use-border style) +border-size+ 0))
            (gravity (ensure-gravity (style-gravity style))))
  +    (setf (gravity-offset-x gravity) (style-offset-x style)
  +          (gravity-offset-y gravity) (style-offset-y style))
       (destructuring-bind (x y w h)
           (compute-popup-window-rectangle gravity
                                           :source-window source-window
  
positive.code:   (let* ((style (popup-window-style destination-window))
           (border-size (if (style-use-border style) +border-size+ 0))
           (gravity (ensure-gravity (style-gravity style))))
      (destructuring-bind (x y w h)
          (compute-popup-window-rectangle gravity
                                          :source-window source-window
  
negative.code:                               (style-use-border style))
                :background-color (if background-color-p
                                      background-color
                                      (style-background-color style))
                :offset-x (style-offset-x style)
                :offset-y (style-offset-y style)))
  
  (defun ensure-style (style)
    (cond ((null style)
  