Ah , finally getting somewhere .

No it’s a project I volunteered to do for these folks:
https://www.facebook.com/groups/1446465172354865
This is my first go-around:
https://www.vmars.us/Guitar/Guitar-Scales-and-Boxes-Builder.html
But it is too finicky , keeps loosing the note , so users have to Drag ultra slow .
So I am working on a (hopefully) faster version .
But It’s a very slow process , here is where I am currently ;
https://www.vmars.us/Guitar/10-CIRCLES-1-IMAGE-CREATE-ELEMENTS-ondragover-Prob.html
and here ;
https://forum.kirupa.com/t/need-help-with-error-insertbefore-on-node-parameter-2-is-not-of-type-node/656450/5