The volume envelope is a great feature! Thanks for letting me know!
If the Specrtalayers manual had more detailed instructions on how to use it, it would be perfect.
Also, if I were to edit harmonics like in AdditiveSynth, it would take a lot of time to split the harmonics into many layers manually, so I would like the ability to change the volume of only the area selected in the specrtal view with an envelope. The eraser tool and amplifier tool alone are not enough.