Only just read this thread some hours after tweaking Compiz resulted in disappearing desktop furniture. I booted into 2D, deleted all things .compiz (in home directory and .config) and to my relief sanity was restored. I shall not try to tweak Compiz to enable easy moving between desktops again.
It occurs to me though that the concept of desktops is no longer really valid. They are not discrete and independent in the sense that they were but bound together by the wretched left launch bar.
Far from this being an improvement over the Classic menu driven system it is something that will cause me to hang on to 11.04 on my mother’s computer for as long as possible because it is far from intuitive.