Ah, yes... I recently modified the overlay bar refresh code (which recalculates every overlay bar button size and visibility, and resizes/shows/hides them) so that it won't be pointlessly ran at every frame, but only when needed and 5 times per second minimum (but the latter check was done in the draw() routine... which is not ran when the bar is hidden !). Some sort of lazy refreshing, if you will... Apparently too lazy however !
Bug fixed for next release.