This seems similar to (if not the same as) the problem I was having: How are separate x screens supposed to work (probable problem)
The white screen is, apparently, caused by nautilus (which can be seen by running
killall nautilus from the terminal). The following page also describes this problem and both a link to a patch that should fix the problem, and a link to a page that tells how to apply that patch: http://ubuntuforums.org/showthread.php?t=1865113
However, that only fixes the white background problem. To get rid of the x cursor and be able to interact with the laptop display, you will need to either,
- Download, install, and use Gnome-Classic. I cannot remember what I did to download and install Gnome-Classic, but I did some searching and I think the following command (run from the terminal) might be what does it:
sudo apt-get install gnome-panel. To use Gnome-Classic, simply click on the gear icon (located near the password prompt) in the login screen and choose it from the list (and then login).
This should allow you to interact with both displays. However, on my computer, when using separate x screens, it removed the toolbar in the first display (not really a problem if you do not mind using the terminal) and, if my first right-click was in the second display, it not only failed, but prevented me from accomplishing further right-clicks in either display.
- Download and install Xfce:
sudo apt-get install xfce4. You should then be able to use it by selecting it from the login screen (by clicking on the gear by the password prompt). If it's not in the list, though, then check the answer given to me in the first link I posted.
This is (in my opinion) the better option, as (for me) it ran without error (as far as I could see). Unless you do not wish to use a different desktop manager, then the first option is usable (however, buggy).