;; time a window is recentered. It is not perfect for our situation,
;; since when it is called for a tail window, it is to late. However,
;; if it is called for another window, we can try to update our
;; time a window is recentered. It is not perfect for our situation,
;; since when it is called for a tail window, it is to late. However,
;; if it is called for another window, we can try to update our