As gilesmartin said this is a feature of Mavericks, nothing to do with DisplayLink.
Each display has it's own menu bar now and the dock can move between monitors.
You'd see exactly the same behaviour if you had a single external monitor connected via the mini-displayport when on Mavericks.
In my case, I have one via mini-displayport and one via a DisplayLink adapter, so I would have three menu bars, one on each screen.
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