When the map engine runs, a part of what it does is call FlipScreen (well, not exactly the same function, but close enough). You can't really use FlipScreen when the map engine is running anyway, at least not to the same effect as when it isn't. It's done for you, so that the map itself renders every frame.
So, FlipScreen is basically for things like Title-Menus and stuff that goes on before the Map is even running, correct?
function MyTitleScreen() { while (true) { //Map engine is paused while in this loop... or rather, it doesn't even get the chance to continue, Sphere being stuck here... RenderMap(); //Display the last known picture of the map font.drawText(100, 100, "Game Title!"); //Drawn on top of that picture //Other drawing stuff maybe FlipScreen(); //Now put it on the screen if (GetKey()) break; //Break out of the loop and continue the map engine if any key is pressed //Keep loopin' otherwise! }}