Today I abandoned Ubuntu in favor of Linux Mint Debian Edition (LMDE) with the Xfce Desktop Environment. I found the new operating system more resources conservative and faster than the previous, so I am really happy with my current configuration.
In my office I use an external monitor in addition to the display of the laptop, and with Ubuntu I worked with an extended desktop. After installing LMDE, the external monitor was still correctly recognized, but the desktop was cloned instead of extended. Therefore, I checked the display properties from the application menù (Settings | Display), but I was unable to configure an extended desktop. Searching on the web, I found a simple and useful GUI for configuring display properties. The GUI is ARandR, and below is a screenshot of the program.
If you came to this post, probably you have the same problem to configure an extended desktop. ARandR perfectly worked for me. Does it work for you too? Let us know by leaving a comment to this post!