A sprite, a text or a panel wholly outside what its camera shows is left out as the frame is collected: not sorted, not laid out, not written for the card, and a map layer draws only the cells the camera shows. A field of small squares and a map of 131,072 cells lie far apart, and a window seen from further out shows what the camera skips.
Click the preview first so it hears the keyboard. The arrows move the camera. X adds 10,000 squares until the FPS drop below your screen's rate, then 1, 2 and 3 look at the squares, the map and nothing. Looking away, the frame gets cheap: only placing each square is left. M takes the map away and back, Z takes squares away.