Ubuntu 12.04 unstable: Launcher and top panel show on top of fullscreen video on second monitor

I use ubuntu 12.04 and have recently connected my HDtv to my computer via hdmi. The problem is, while watching a movie on my tv via the computer, the launcher and top panel pop up when someone is doing something on the computer.

Example:

I start vlc, open a movie and drag it to my tv (second monitor) and set it to fullscreen. It starts playing perfectly on my tv (sound also via hdmi)

My girlfriend wants to check her mail on the computer and opens a web browser. On the TV, the movie keeps playing fine, but the unity top panel and launcher pop up OVER the movie. This is quite annoying.

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I think that the top panel and launcher should NEVER be visible on top of fullscreen video, nor on the first screen, nor on the second. Fullscreen video should always be on top, whatever happens underneath. In this sense it has nothing to do with hiding the panel or launcher on the second monitor, that's another issue, I believe.

David