Dual-screens in U12.04 is not well implemented. As many have reported, either popups appear on the "other" screen to the application that launched them, or new applications launched by clicking on images, files etc, all seem to open in the left-most-screen. Somehow, at least on Thinkpad using NVIDIA, the left-most screen seems to always launch new application windows when the app is launched indirectly, say from Nautilus actions like "open" or "edit".
Dual-screens in U12.04 is not well implemented. As many have reported, either popups appear on the "other" screen to the application that launched them, or new applications launched by clicking on images, files etc, all seem to open in the left-most-screen. Somehow, at least on Thinkpad using NVIDIA, the left-most screen seems to always launch new application windows when the app is launched indirectly, say from Nautilus actions like "open" or "edit".