How is it possible?
I installed a treeview module. I followed all the documentation and the module is showing. Perfect!

Me: create 3 roots,
Module: all is ok.
Me: 😊create 2 nodes,
Module: everything is fine.
Me: 😁3rd node
Module: ... Kaput. tree displays like the nodes are in random order.

Me: 🤨Check the database, and fix the set.
Module: Aah much better.
Me: 😃Try to change an int.
Module: Noooooo! Big mistake!!!
Me: 🤔Ok, ok, ok, rollback! 😧
Module: still in random situation
Me: 😶 and now what?