Here are some notes that might be helpful if you're experiencing problems getting desktop effects to work in Ubuntu Intrepid Ibex 8.10, after enabling dual monitor or dual head support. In my case, the problem is the Intel driver not supporting a high enough texture size. This is not yet fixed in 8.10, but should be at some point. Here is the link: The problem is that compiz is checking GL_MAX_TEXTURE_SIZE and failing if the value is not as high as the Virtual Screen size that's set in xorg.