selects a scale and identifies the notes for that melodic scale Qtractor has that feature, but you may have it hidden. In the editor menu: View>Toolbar>Scale In this screenshot, below the Beat indicator, you can see the scale: C Chromatic https://www.qtractor.org/image/qtractor-screenshot12.png It is true that the note tracks that do not correspond to the scale are not grayed out (indicating disabled), but it will only allow you to edit notes within the scale. Reply
Qtractor has that feature, but you may have it hidden.
In the editor menu:
View>Toolbar>Scale
In this screenshot, below the Beat indicator, you can see the scale:
C Chromatic
https://www.qtractor.org/image/qtractor-screenshot12.png
It is true that the note tracks that do not correspond to the scale are not grayed out (indicating disabled), but it will only allow you to edit notes within the scale.