== cascade cue selection (depth -> combo cue) ==
depth 0 -> idx 0 ([sx] audio: cue combo1)
depth 1 -> idx 0 ([sx] audio: cue combo1)
depth 2 -> idx 1 ([sx] audio: cue combo2)
depth 3 -> idx 2 ([sx] audio: cue combo3)
depth 4 -> idx 3 ([sx] audio: cue combo4)
depth 5 -> idx 4 ([sx] audio: cue combo5)
depth 6 -> idx 4 ([sx] audio: cue combo5)
depth 7 -> idx 4 ([sx] audio: cue combo5)
depth 8 -> idx 4 ([sx] audio: cue combo5)
depth 9 -> idx 4 ([sx] audio: cue combo5)
ok: cascade cue mapping clamps into combo1..combo5