I have a macbook pro late 2011 with mavericks 10.9.3, and installed DisplayLink v2.2.
I have two BENQ monitors, one is connected to MBP via 'apple-mini-dvi-to-dvi-adapter', and another is connected to MBP with a DisplayLink device.
Left one is via 'apple-mini-dvi-to-dvi'
Right one is via DisplayLink
You can see if I put menubar on MBP, the black apple icon on left of the menubar of DisplayLink connected monitor does not display appropriate.
But if I move menubar to DisplayLink connected monitor, it displays well.