Thanks! Do you see any error messages in the console? (Right click anywhere, "Inspect", then click on the "Console" tab, and try to drag and drop -- if any error messages pop up, that would help me debug)

Hmm I think it's because your fork is loading a newer version of d3. If you change the d3 import to this (so that it loads version 5): d3 = require('d3@v5') then it should work.

Sounds good, I will mark this as resolved!