Hello,
It works with the last beta, but if you configures the diagram this way the diagram doesn't show anything:
MultipleParent.DiagramModel.Constraints = Syncfusion.JavaScript.DataVisualization.DiagramEnums.DiagramConstraints.Default
| Syncfusion.JavaScript.DataVisualization.DiagramEnums.DiagramConstraints.Routing
| Syncfusion.JavaScript.DataVisualization.DiagramEnums.DiagramConstraints.Bridging
;