Inheriting BindingList(Of T)

[taxair]

Please see the below example:

Imports System.ComponentModel

Public Class level1Collection(Of T As level1Item)
    Inherits BindingList(Of T)

    Public Sub Load()
        Dim i As T = Me.AddNew
    End Sub
End Class

Public Class level2Collection(Of T As level2Item)
    Inherits level1Collection(Of level2Item)
End Class

Public Class level3Collection(Of T As level3Item)
    Inherits level2Collection(Of level3Item)
End Class

Public Class level4Collection(Of T As level4Item)
    Inherits level3Collection(Of level4Item)
End Class

Public Class level1Item

End Class

Public Class level2Item
    Inherits level1Item
End Class

Public Class level3Item
    Inherits level2Item
End Class

Public Class level4Item
    Inherits level3Item
End Class


Public Class Worker
    Sub New()
        Dim c As New level4Collection(Of level4Item)
        c.Load()
    End Sub
End Class

'************** *************** ***************
'Basically I have 4 levels of inheritance, representing the core object all the way through the application level object. When I create "c" in the worker object. It creates a bindinglist(of level4items). When I call c.Load. which is inherited from the level1collectio n, the item that is created in the Me.AddNew is a level2item, not a level4item. Why is the base list creating in object from level 2 rather than level 4? The "type" of "Me" when I look in the level1collectio n is as follows

{Name = "level4Collection`1" FullName = "DemoApp.level4Collection`1[[DemoApp.level4Item, DemoApp, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]"}
    System.RuntimeType: {Name = "level4Collection`1" FullName = "DemoApp.level4Collection`1[[DemoApp.level4Item, DemoApp, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]"}

Yet it still creates a level2item.

Thank you in advance, this is a simplified question to a rather large problem i'm facing.

Thanks.