I've got a Dell XPS 15 L502x laptop, with a NVIDIA GeForce GT540M graphics card using the Optimus duel system. I've purchased an external monitor that I can connect with HDMI to act as a second display. It works fine under the duel-booted Windows 7, but I've been having a lot of problems getting it to work with Ubuntu.
I have the screens set up with the larger monitor on the left and the smaller laptop on the right. If I try and move my mouse from the monitor to the laptop screen instead of just "jumping across" as you would expect the display on the larger monitor instead pans to follow the mouse. This only happens on the larger screen if you move your cursor from left to right. You get a large blue box of "dead space". You can't move your cursor there, but for some reason it still counts as part of the desktop. So, for example, if you maximise a window it will expand over the whole area making the top right corner completely inaccessible.
An even worse issue is that windows can still pop-up there and be inaccessible using the mouse.
This problem does persist if I set the larger monitor's resolution to that of the laptop display. So instead of moving from screen to screen the cursor just pans the display between the two. It's very strange.
I think it might be in some way connected to the Nvidia graphics card. If I open System settings > Screen display it shows both screens in the right positions. But if I open the Nvidia X server settings it only recognises, for some reason, the external monitor and not the laptop screen. Here's a screenshot. I can't find any information about this, I find it especially odd that it's recognising the external display but not the built-in one?
Any help would be greatly appreciated. All this makes Ubuntu pretty much unusable with the second monitor, which is a great shame. Especially since it works fine on Windows, I'm going to have to resort to using that to justify the purchase.
It's probably worth noting this occurs whether I'm using Ubuntu Unity, GNOME 3 or GNOME Classic (and there are plenty of other errors I'm finding trying to use any of them with multiple monitors, this is just the biggest). I'd certainly be open to any suggestions of any other other desktop managers or even different distributions that might work with this setup.
After searching around I found Nvidia X Server Settings only shows 1 screen (laptop + external monitor connected) which seems to have a similar issue with regards to only one monitor showing up in the Nvidia X settings, though no mention of the panning problem.
EDIT: I completely reinstalled Ubuntu GNOME, then installed the nvidia drivers and
lightdm. First time I connected the external monitor it worked perfectly, the two screens were separate. Then I restarted and the exact same problem is back, with nothing obviously done to cause it.