Ok, I read Unity has problems when in dual screen mode, but this seems something different from the bug I read filed.
As soon as I attach the secondary screen I get both screens completely screwed up like the image attached. Here something about the desktop can be seen, some other times only lines could be seen.
I'm using ATI with opensource drivers and kernel 2.6.39 (2.6.38 wasn't working and 2.6.35 was doing the same). Do not suggest please to install proprietary ATI drivers cause on 11.04 those won't install. Still investigating why, in case I'll ask another separate question :-)
Anyone else experiencing the same? Have you ever encountered a similar bugreport? Should I report this? Thanks!