there should be multiple resolutions available in the game itself. Choose one thats a full resolution. It will also have one that has a slight amount of pixels missing from the Y value... like if your fullscreen is 1280x800, there will be an option that is 1280x778... it'll be missing some pixels. If you choose the resolution missing some pixels, it will run on the desktop wallpaper and not cover the Dock and Menubar. Choose the correct in game resolution inside the game itself, and it should go fullscreen.