Unity launcher autohide leaves "ghost" behind?

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http://askubuntu.com – In 12.04 I had the launcher set to autohide, which worked perfectly. However in 12.10 I am getting a strange "ghost" issue. Take this screenshot, with me having a maximised google chrome window, mousing over the back button. As well as this, I also get another ghosting issue when I have the panel set with an opacity, whereby whatever is in approximately the middle left of the screen gets mirrored up to to panel, but only when I move/switch to a window. But that one is not so annoying as the autohide bug, how can I fix that? (HowTos)