I’m not sure I understand the situation. Do you know about TreeLayout.sorting and TreeLayout.comparer?
Would you want to perform a layout at the end of each move? If so, implement a “SelectionMoved” DiagramEvent listener that calls myDiagram.layoutDiagram(true).
Yes, instead of having the comparer function depend on some property of each vertex’s node’s data (.node.data.sequence in that forum topic), have it depend on the TreeVertex.node.location.x.