void afterCreate() {
DrawingManager2 drawingManager = _sheet.getWorkbook().getWorkbook().getDrawingManager();
short dgId = drawingManager.findNewDrawingGroupId();
_boundAggregate.setDgId(dgId);
_boundAggregate.setMainSpRecordId(newShapeId());
drawingManager.incrementDrawingsSaved();
}
/**
* Creates a new group record stored under this patriarch.
*