When I was working on the implementation of the wxScrolled<> autoscroll, my experience with the drawing sample seemed to show that the coordinate system was client points. However, today I used GetRect() on the dnd sample DnDShapeFrame, and it appears to be reporting GetRect() with screen coordinates.
Am I correct to think that windows for which wxWindow::IsTopLevel() is true report GetRect() with screen coordinates, but if wxWindow::IsTopLevel() is false, GetRect() returns client coordinates? If so, then there is a bug in the new wxScrollHelperBase::AutoscrollTest().