A lot of producers this days don’t know how to use scales such as major, minor (natural, harmonic, melodic), chromatic, etc. I find this scale button on studio one’s piano roll maybe it’ll be sweet to add yours with this kind of add ons on the piano roll?
Double-click a tempo event (above the tracks, the thing that says “4/4 120 bpm”). You can choose a scale from the list or enable notes to create a custom scale. You can edit the notes region editor profile to dim note lanes not belonging to your scale instead of dimming black keys’ lanes.
This is just a visual guide. The note editor (MIDI editor) will NOT force your input notes to the selected scale.