MrEd is essentially a marriage of MzScheme and the wxWindows class library. This manual describes how to use C++ structures (i.e., the wxWindows/wxMedia class libraries) from MrEd.
This manual assumes familiarity with MzScheme, which is described in Reference Manual for MzScheme. The typesetting sources are taken from Julian Smart's Reference Manual for wxWindows 1.60: a portable C++ GUI toolkit.