haven't noticed this on any 10.8.2 machine i've used recently but it was one of the very first things i noticed on this refurb retina. the top menu bar just darts away, particularly when i'm swapping programs (alt-tab, etc.) and will spontaneously reappear when i do it again. do i have a bad refurb or is this a known issue? shall i swap her over or is there a fix? thanks!