If you use selection markers when implementing a subWorldDraw() or subViewportDraw() function, you must set the first selection marker before making any AcGiWorldGeometry or AcGiViewportGeometry call that generates graphics primitives, including calls to the mesh() and shell() functions. If necessary, you may set this first marker to an artificial value such as -1.
The first time in each drawing that AutoCAD encounters an entity that does not follow this rule, a message box is displayed informing the user that the drawing contains entities that do not conform to the AutoCAD graphics API. This non-conformance is detected when geometry is received before the first subentity marker.