Harmonic enabler, what does it do

Hello,
I have noticed that both in Traktor DJ2 for iOS and Mac I can tap to enable and disable the Harmonic indicator of the songs in the Layout (the one between the song name and the bit number/downbeat setter). I see no effect on enabling and disabling it... what does it exactly do?

 

It probably turns off Key Lock?

 

Thanks. I have not found too much information of what Key Lock is in Traktor DJ videos and threre is not much docs on it (all reference talks about other Traktor software that have this Harmonic feature too).

So you mean disabling Key Lock should make the song adapt to the other playing song's key?

 

yes, its keylock on/off.

On (highlighted icon) means that even in case you change tempo (pitch fader or bend knobs) the pitch of the songs will not change (e.g. a 11m song is always a 11m song even if you change tempo/bpm). Test it once in jogwheel view and rise fader or use <> buttons. You will hear the difference for sure .
This makes harmonic mixing more easy. (btw: the key symbol is now also added in track browser recommended song list to find a song with same key)
in case you need support, use this forum better: https://www.native-instruments.com/forum/forums/traktor-dj-2.411/