Private properties of the PropertyFieldSortableList custom field.
We separate public & private properties to include onRender & onDispose method waited
by the PropertyFieldCustom, witout asking to the developer to add it when he's using
the PropertyFieldSortableList.
Private properties of the PropertyFieldSortableList custom field. We separate public & private properties to include onRender & onDispose method waited by the PropertyFieldCustom, witout asking to the developer to add it when he's using the PropertyFieldSortableList.