The Note Pro lets you run up to four apps that way. That means having Gmail on the upper left portion of the screen, while YouTube video plays on the upper right, a Web browser opens on the lower right and a chat app runs on the lower left. You can change how much space each app takes and save configurations so that you don't have to open the four apps individually each time.
If you want to run more than four, you can activate Pen Window. Apps open in a window that floats over the main app on the screen. You can have several apps open at once, and you can temporarily set an app aside by minimizing it into a small dot.
