Telerik.Web.UI.OrgChartDrillDownEventArguments.SourceNode.get returns Nothing

[Gerhard Krenn]

I try to follow the example in https://demos.telerik.com/aspnet-ajax/orgchart/examples/applicationscenarios/drilldowntoviewdetails/defaultvb.aspx?show-source=true but if I run the code and click on an icon for drill-down I get the error at the line "If e.SourceNode.ID <> "1" Then":

Telerik.Web.UI.OrgChartDrillDownEventArguments.SourceNode.get returned Nothing.

The code is:

  Private Sub RadOrgChart2_DrillDown(sender As Object, e As Telerik.Web.UI.OrgChartDrillDownEventArguments) Handles RadOrgChart2.DrillDown
      If e.SourceNode.ID <> "1" Then
          Dim item = New OrgChartGroupItem()
          e.SourceNode.Renderer.Controls.Remove(e.SourceNode.Nodes.Renderer)
          e.SourceNode.GroupItems.Clear()
          e.SourceNode.Nodes.Clear()
          e.SourceNode.GroupItems.Add(item)
      End If
  End Sub

Please advise!

Thx
Gerhard