When working in Mavericks and using mission control you move a fullscreen vm from one monitor to the next, there is a ghost gray menu bar that has no text, but is clickable. I think this might be a bug in Mavericks, as I see it in other systems. However, can you just add a feature or something that just always shows OSX's menu bar in fullscreen (either monitor)?
Otherwise, how do you get rid of that ghost menubar?