A ChoiceActionItem object that represents the Single Choice Action's item which is currently selected.
Use this property to specify the Single Choice Action's item which is displayed as a selected item in a UI. Manual changing of this property value raises the SingleChoiceAction.SelectedItemChanged event. However, when an end-user changes this value by selecting an item in the Action's control, the SingleChoiceAction.Execute event is raised.
You may need to use this property and the corresponding event when implementing a custom Action Container.