Update Lab.java display method; was displaying too much

src/main/java/nl/tudelft/ewi/queue/model/Lab.java

@@ -537,7 +537,8 @@ public class Lab implements Serializable {
 
 	public boolean display() {
 		return (now().isAfter(slot.getOpensAt()) && slot.getClosesAt().plusMinutes(15).isAfter(now())) ||
-				(signOffIntervals && now().isAfter(slotSelectionOpensAt));
+				(signOffIntervals && now().isAfter(slotSelectionOpensAt) &&
+						slot.getClosesAt().plusMinutes(15).isAfter(now()));
 	}
 
 	public boolean hasRoom(Room room) {