This is a read-only property that returns a boolean indicating if the Infragistics.Win.AppearanceBase of the HeaderAppearance has been created. The appearance is lazily created only when requested to reduce overhead.
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