The BROWSE encoder, at the top of the Mixer.
1. Hold
SHIFT and turn the BROWSE encoder to scroll through the Browser Tree.
2. Hold SHIFT and press the BROWSE encoder to expand/collapse a folder node in the
Browser Tree.
3. Release SHIFT and turn the BROWSE encoder to scroll through the tracks of the currently
highlighted Playlist.
You can see the items being scrolled in the TRAKTOR Browser:
Hardware Control Reference
Browsing, and Loading
Traktor Kontrol S2 - Manual - 130