node.render(true) with table extension is sorting node to end of the table

[hglty07]

Expected and actual behavior

When updating part of the tree with enabled table extension and node.render(true),
the updated nodes are sorted to the end of the table, i expected them to remain at the original position.

Steps to reproduce the problem

1. Tree with table extension
2. call node.render(true) for toplevel-node

Environment

• Fancytree version: 2.20.0
  enabled/affected extensions: ext-table

[mar10]

This only happens if node is the first sibling