Un sottomenu a runtime...

Come si aggiunge un sottomenu a runtime a un contextmenu?

 Private Sub Form1_Load(sender As Object, e As System.EventArgs) Handles Me.Load
        matrice(0) = "Tizio"
        matrice(1) = "Caio"
        matrice(2) = "Sempronio"
        For n = 0 To matrice.Length - 1
            Dim mn As New ToolStripMenuItem
            mn.Text = matrice(n)

            Menu.Items.Add(mn)
        Next
        For Each elemento In Menu.Items
            If elemento.Text = "Sempronio" Then
                Dim submenu As New ToolStripMenuItem With {.Text = "ciccio"}
                elemento.DropDownItems.Add(submenu)

            End If
        Next
    End Sub

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