I have found out this wrong behavior when rendering both top and bottom data list.

Let's say we have a top list = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], and a bottom list = [11, 12, 13, 14, 15, 16, 17, 18, 19, 20],
then the combined values would be [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20].

Current logic
final caculationCurrentIndex = controller._top.length - index;

The current calculationCurrentIndex of index 0 for top list is wrong as it is supposed to be started at 9-indexed, instead of 10-indexed.