Code:
            m_copyCodiceButtonDef = m_inventorApplication.CommandManager.ControlDefinitions.AddButtonDefinition( _
                "Codice -> Clipbpard", _
                "CopyCodiceIntName", _
                 CommandTypesEnum.kEditMaskCmdType, _
                 m_ThisGuidString, _
                 "Copy the codice to the clipboard", _
                 "Copy the codice to the clipboard")
            AddHandler m_copyCodiceButtonDef.OnExecute, AddressOf CopyCodiceCommand
            m_checkSelectButtonDef = m_inventorApplication.CommandManager.ControlDefinitions.AddButtonDefinition( _
                "Check Selection", _
                "CheckSelectionIntName", _
                 CommandTypesEnum.kEditMaskCmdType, _
                 m_ThisGuidString, _
                 "Provide info of the selection", _
                 "Provide info of the selection")
            AddHandler m_checkSelectButtonDef.OnExecute, AddressOf CheckSelectionCommand
            m_splitButtonDef = m_inventorApplication.CommandManager.ControlDefinitions.AddButtonDefinition( _
                "SplitButton", _
                "SplitButtonIntName", _
                 CommandTypesEnum.kEditMaskCmdType, _
                 m_ThisGuidString, _
                 String.Empty, _
                 String.Empty)
Private Sub m_UserInputEvents_OnLinearMarkingMenu(ByVal SelectedEntities As Inventor.ObjectsEnumerator, _
                                                          ByVal SelectionDevice As Inventor.SelectionDeviceEnum, _
                                                          ByVal LinearMenu As Inventor.CommandControls, _
                                                          ByVal AdditionalInfo As Inventor.NameValueMap) _
                                                          Handles m_UserInputEvents.OnLinearMarkingMenu
         Dim selectedEntity As Object = SelectedEntities.Item(1)
         If TypeOf selectedEntity Is Inventor.ComponentOccurrence OrElse _
            TypeOf selectedEntity Is WeldmentComponentDefinition OrElse _
            TypeOf selectedEntity Is AssemblyComponentDefinition OrElse _
            TypeOf selectedEntity Is PartComponentDefinition Then
            Dim buttonDefinitions As ObjectCollection
            buttonDefinitions = m_inventorApplication.TransientObjects.CreateObjectCollection
            buttonDefinitions.Add(m_copyCodiceButtonDef)
            buttonDefinitions.Add(m_checkSelectButtonDef)
            LinearMenu.AddSplitButton(m_splitButtonDef, buttonDefinitions, False, True)
         End If
End Sub