If GDI+ is available, the tree control supports additional features not otherwise available:
GDI+ is always available on Windows XP, Windows Server 2003, Windows Vista and newer Windows versions. On earlier Windows versions, GDI+ is available as a redistributable for Windows 2000, Windows 98, and Windows Me from Microsoft (http://microsoft.com) as part of the Platform SDK (Windows XP and newer). Usually, it is sufficient to simply distribute the Dll gdiplus.dll in your application directory.
If GDI+ support is not available, the features are simply disabled and alternate presentation methods are used, if available.
An application can test whether GDI+ is available using the GDIPlusSupport property.