PGN viewer where you can copy and paste lines and subtrees?

I've looked at Scid and ChessX and a few other PGN viewers, but none seem to allow you to copy and paste lines and subtrees from and to PGN files? Is there any such thing out there?

Maybe something that can present a nice tree view and the ability to click on a node and copy subtree or something.

I am looking to copy whole subtrees in my repertoire where there are transpositions.

I know I can do it by hand, but locating a specific position arrived at through a specific move order is not that easy by hand.

I was never able to find one, so I ended up writing my own python scripts to accomplish the same things:
https://github.com/olleeriksson/pgn-tools

- Merge PGN files including comments (normal and software comments).

- Inject transpositions into PGN files.

- Get subtrees from a PGN file.