You guys do realize that this is not a bug or error.. It's a feature, the small portion you are referring to is the actual homescreen.. When you select a wallpaper it's a sort of cross. Why is it a cross? Well when you open the app drawer the wallpaper scrolls down to give another perspective.. So basicly, the horizontal bar of the cross is the actual wallpaper on the homescreen. The vertical bar is for scrolling up in the app drawer. If you don't want that move to another launcher, or set wallpaper scrolling to off.