VBA Excel: Como agregar un item al menu de boton derecho.

Para agregarlo:

Sub addtoshortcut()
Dim bar As CommandBar
Dim newcontrol As CommandBarButton
deletefromshortcut
Set bar = Application.CommandBars("Cell")
Set newcontrol = bar.Controls.Add _
    (Type:=msoControlButton, ID:=1, _
    temporary:=True)
    With newcontrol
        .Caption = "&Container Count"
        .OnAction = "containercount"
        .Style = msoButtonIconAndCaption
    End With
End Sub

Para dejarlo como estaba:

Sub deletefromshortcut()
    On Error Resume Next
    Application.CommandBars("Cell").Controls _
    ("$Container Count").Delete
End Sub