Hello. in certain instances It may be good to be able to soften up these selections when deleting them.
to be able to grab a greater range to delete, without hard edges sort of allows quicker workflow and better results. I also use this tool sometimes in conjunction with the eraser tool, so if the harmonics tool had these parameters it sort of bridges the gap a bit and I can make better workflow decisions.
You may want to consider making the parameters proportional in ratio to the harmonics size/frequency. ie, the fundamental frequency having the broadest Fade range and the highest harmonic having the more minimized fade range. Otherwise, the setting you set for the fundamental may not make sense for the highest.
This is also another instance where being able to change the tool parameters after a selection and have them reflect so on the spectragram.
example: If I make a harmonics selections with 5 harmonic limit, but then I decide I actually need 6… allow the user to make that change instead of having to redo their selection.