I just bought a boat with networked Humminbird Helix 7 GPS G3N units at the bow and at the console. The console unit starts and the view takes up the whole height and width of the screen. The bow unit has a black area about 1 inch wide on each side and 3/4 inch high at the top and bottom of the screen. They are networked and I did not have both units one when I turned on the bow unit. Am I missing a setting?