This does not apply to items whose keys are null or empty. There can always be multiple items with null or empty keys unless the Infragistics.Shared.KeyedSubObjectsCollectionBase.AllowEmptyKeys property returns false.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2