If you resize the window, the text area is immediately updated, but the top status bar suffers from a 1 second delay (unless -keepup is specified).
Having keepup disabled makes sense for slow connections as it really saves a lot of traffic. But when you resize the window, joe has to output lots of text anyway, refreshing the top status bar wouldn't increase it that much. So it would be very nice if joe immediately updated the whole screen, including the top status bar after a window resize, even when keepup is disabled.
(NB. I often use joe over ssh and always have keepup enabled, and it never caused any problem. Knowing how much Internet's speed has changed since you started developing joe, I'd also consider making -keepup the default.)