fix sliders disappearing when multiple sliders are active or when later sliders is done earlier (2b maps etc)

src/itdelatrisu/opsu/Utils.java

@@ -661,4 +661,13 @@ public class Utils {
 		};
 	}
 
+	public static class Pair<F, S> {
+		public F first;
+		public S second;
+		public Pair(F first, S second) {
+			this.first = first;
+			this.second = second;
+		}
+	}
+
 }