We are creating a diagram at runtime:

Dim WithEvents diagram As New MindFusion.Diagramming.Wpf.Diagram

... Some events seem to fire and others do not.

This works:
    Private Sub diagram_NodeSelected(ByVal sender As Object, ByVal e As MindFusion.Diagramming.Wpf.NodeEventArgs) Handles diagram.NodeSelected

This does not:
    Private Sub diagram_NodeDeleting(ByVal sender As Object, ByVal e As MindFusion.Diagramming.Wpf.NodeValidationEventArgs) Handles diagram.NodeDeleting

Drag/Drop events also don't seem to fire. 
    Private Sub diagram_Drop(ByVal sender As Object, ByVal e As System.Windows.DragEventArgs) Handles diagram.Drop

But the objects within the diagram do move around as we drag them.

Any idea what we are doing wrong?