Using OS X 10.8.4. Frequently, when changing spaces, the menu bar from the app that had the focus on the last-displayed space is left behind. In other words, say I have Mail on one space and Safari on another. I’m focused on Mail’s space, then switch to Safari. I’ll see the Safari window and Mail’s menubar. I need to click once (sometimes more than once) on Safari’s dock icon to force its menubar to appear. Sometimes it never appears.
I’m just using Safari and Mail here as an illustration. This retentive menubar can occur with any application and any space.