I installed a clean precise. I like gnome-shell so I installed it. It worked well with single monitor. But It does not work well when I go to office, plug my external monitor onto my laptop. I am using nvidia driver. Another colleague is using the same laptop, he can work well with dual monitors. His laptop is ATI graphic card.
When I plug my extended monitor cable, I choose GNOME, but actually it goes to gnome 2 classic desktop environment, not GNOME 3. When I disconnect the extended monitor, restart X, I can login with GNOME3. Do I have to choose between GNOME3 and extended monitor? It's a hard choose.