I'm having this same problem on an up to date installation of Oneiric. I notice it most frequently when running Chrome fully maximised, no other applications running. Unity launcher also sometimes does not close when in dodge windows mode. I have discovered that by dragging an icon, picture, etc. over the launcher but not dropping it there causes it to properly hide again.
I'm having this same problem on an up to date installation of Oneiric. I notice it most frequently when running Chrome fully maximised, no other applications running. Unity launcher also sometimes does not close when in dodge windows mode. I have discovered that by dragging an icon, picture, etc. over the launcher but not dropping it there causes it to properly hide again.