B4J Question Textarea ScrollChanged event?

Sub AppStart (Form1 As Form, Args() As String)
    MainForm = Form1
    MainForm.RootPane.LoadLayout("Layout1")
    MainForm.Show
    Dim jo As JavaObject = TextArea1
    Dim event As Object = jo.CreateEventFromUI("javafx.beans.value.ChangeListener", "ScrollChanged", Null)
    jo.RunMethodJO("scrollTopProperty", Null).RunMethod("addListener", Array(event))
End Sub

Sub ScrollChanged_Event (MethodName As String, Args() As Object) As Object
    If MethodName = "changed" Then
        Dim NewPosition As Double = Args(2)
        Log(NewPosition)
    End If
    Return Null
End Sub