Extension method for xojo.Core.Dictionary

It seems that it is not possible to use Extension methods with xojo.Core.Dictionary?

It works here. Make sure you create your extends method on a module.

[code]Module Module1
Sub Test(Extends d As xojo.Core.Dictionary)
MsgBox CurrentMethodName
End Sub
End Module

// In App.Open() event
Dim d As New xojo.Core.Dictionary()

Thanks für your answers.
It works, but I have no code completion.