Probably a stupid question, but I'm a droid newbie, and I can't figure out how to close certain apps when I'm done using them. For instance, on Google Maps, I can't find an exit button. If I simply press the home key, my Google navigator will continue running in the background, a problem that I heard will drain the battery quickly. So how to I close the window, and how do I ensure that the whole app is closed as well? Thank you!