With the introduction of Windows XP, GDI was deprecated in favor of its successor, the C++ based GDI+ subsystem. GDI+ is an improved 2D graphics environment, adding advanced features such as anti-aliased 2D graphics, floating point coordinates, gradient shading, more complex path management, intrinsic support for modern graphics-file formats like JPEG and PNG (which were conspicuously absent in GDI), and general support for composition of affine transformations in the 2D view pipeline. GDI+ uses ARGB values to represent color. Use of these features is apparent in Windows XP's user interface, and their presence in the basic graphics layer greatly simplifies implementations of vector-graphics systems such as Flash or SVG. The GDI+ dynamic library can be shipped with an application and used under older versions of Windows.
Not sure if it's related to the same GDI+ in the addon.