Looking for drag and drop hierarchical object list editor/manager

I'm looking around for drag and drop hierarchical editing functionality that
I can use, for a small personal project I would like to build.

I'm looking to group, ungroup, add, delete, promote, demote, and move list
items in a list pane, primarily using drag and drop capabilities within my
little project.

There would be next-level-roll-up list items auto-generated corresponding to
groups that exist in the list.

My list objects would be table row or line items with edit logic independent
from the list editing logic, so I guess the answer can be more generic than
just line items.

I thought since Smalltalk has various visual hierarchies there might be some
tools around.  

Are there any widgets, objects, or tools around that would help me build
this sort of thing into my own little project?

I'm taking this route because most of the technology has a lot changed since
I worked with Smalltalk many years ago, and I never was great with graphic
event programming, so I don't know that I could roll my own without taking
an inordinate amount of time.

Any help or suggestions would be greatly appreciated.

Sincerely, JS





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Seniorius Lurkius
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