anchor.diff:  (defun collect-bottom-windows (window-list)
     (lem-utils:max-if (lambda (window)
                         (+ (window-y window)
  -                         (window-%height window)))
  +                         (window-height window)))
                       window-list))
   
   (defun %shrink-windows (window-list
  
positive.code:                        (window-width window)
                         (- (window-height window) height)
                         t)))
      (setf (window-%height window) height)
      (split-window-after window new-window :vsplit)
      (lem-if:split-window-vertically (implementation)
                                      (window-view window)
  
negative.code:       ;; return minus number
        (window-cursor-y window)
        ;; return zero or plus number
        (let ((height (- (window-height window)
                         (if (window-use-modeline-p window) 1 0))))
          (max 0 (- (window-cursor-y window)
                    (1- height))))))
  