Oftentimes on your Ubuntu system you will need to launch applications using sudo (or a graphical form of it) if you're changing critical system settings or doing other tasks that need special privileges.
However, once you have opened up a GUI tool under sudo, it can be difficult to tell the difference between an application running with normal privileges and one running at the root level.
Lifehacker have a really neat trick that allows you to change the graphical look of applications launched with root privileges, so you can easily tell the difference.
A quick way to visually separate your simultaneous sessions, is to assign a different theme to your sudo applications. To do this, open a terminal and type the following:sudo gnome-theme-manger
Pick a new theme, and any time you launch an application using sudo, you will be able to clearly see the difference between your sudo windows and your regular windows.
Very handy!