Thanks for the answer, I would like to learn how to use that function properly, I mean, whats the porpuse of having the scale in the Chord Track.
I already have found how to unblock the option to edit the scale shown in the chord track (uncheck the authomatic scales option to the left of the MIDI Track), and what now?
Hello Ramiro !
The scale will change from the chords you choose. Because the scale are dependent of the chords and degrees you choose.
About the scale, they are correct
in D#Major scale on your picture you have your :
Cmin chord (6 degrees/C Aeolian)
Gmin (third degrees / G Phrygian)
Abmaj (forth degrees / Ab Lydian)
And in your Dmajor scale you have :
Amaj (fifth degrees / A mixolydian) wich for this one is a dominante chord
So you can trust the scale 
they are correct, but again you don’t have to worry of them because what rule first are the chords you choose from your playing or the audio you transfer to midi.
The only thing then (i don’t have my nuendo in front of me) you can choose in your track options for further midi piano roll post editing (or live playing) to be dependent to Scale or Chords or Both.
Thanks for replaying. Thats the thing, it seems like the musical passage with Cm - Gm - Ab is in the Key of Eb (D#), but in reality we are in the Key of Gm: Cmin (iv) and Gmin (i). You can tell because of the notes of the melody (G,A,Bb,C,D,Eb,F,G) and when Abmaj appears, now the melody is in a lydian mode (coincides with the scale Cubase proposes).
Any way, altogh I have figured out how to change the scale, I don´t know what cai I do with that information. For instanse: I can take a chord from the Chord track and drag it into an instrument track or a MIDI track, and I will have the notes of that chord written down as MIDI notes, but I Can´t do that if I take the scale and drag it. So, how can I use that scale into a project?
Tanks for your time
You can utilize the scale e.g. in the Key Editor. You can have only the pitches of that scale being displayed. Or you can midi live input automatically corrected to the scale.
For tracks you can have their content be adjusted to fit the scale.
Johnny_Moneto describe exactly what you can do with the scale.
Hope his answer help
I use the Chord Track on nearly every Project. For me the most useful scale based feature in the Key Editor is the ability to color-code Notes based on the Chord Track. This lets you see at a glance if a Note is in the Chord, the Scale, both the Chord & Scale, or neither the Chord or Scale. This is particularly useful in melodic writing where non-chordal, but still in the scale, tones can be quite common.
Also it looks like you have Automatic Scales enabled. I always have that turned off so I can manually set the scale I want - when & where I want. With Automatic Scales enabled anytime you add a chord that has a note outside the current Scale it will change the Scale to a new one that does contain all the Notes in the current Chord.
But that’s not very useful musically. Say I’ve got a song in C Major and at some point I do a major-minor chord substitution of a Dm to a D chord. Automatic Scales would add a New Scale Event changing the key to something like D Major. But from my perspective the Scale isn’t changing from C Major, I’m just adding a bit of color to the chord progression. With Automatic Scales disabled, the Key Editor will color-code the F# as not being in the current Scale (C Major) but is in the current Chord (Dm) - which is pretty much what’s happening.
