I’ve got a MIT-licensed 3D file and data manager app in development, which allows you to drag and drop groups of folders around. However, when you drag a folder, it falls more and more out of alignment with the rest of the folders in the group, and i haven’t been able to figure out why this happens.
https://jsfiddle.net/rveerman/sceguyvf/37/ adds debugger statements in the relevant areas…
with the help from ##javascript at freenode IRC servers, i managed to get it working! 
live demo (soon) at 3D file manager on nicer.app
source codes at nicerapp_v2/na3D.source.js at ed7f7cb73a77fab12222ce879a367b0bb5c9bb9a · nicerapp/nicerapp_v2 · GitHub