@Override public void addChild(FXGNode child){
  if (child instanceof GraphicContentNode) {
    if (children == null)     children=new ArrayList<GraphicContentNode>();
    GraphicContentNode graphicContent=(GraphicContentNode)child;
    graphicContent.setParentGraphicContext(createGraphicContext());
    if (child instanceof GroupNode) {
      if (isInsideScaleGrid()) {
        throw new FXGException(child.getStartLine(),child.getStartColumn(),"InvalidScaleGridGroupChild");
      }
    }
    children.add(graphicContent);
  }
 else {
    super.addChild(child);
  }
}

@ Override public void addChild ( FXGNode child ) { if ( child instanceof GraphicContentNode ) { if ( children == null ) children = new ArrayList < GraphicContentNode > ( ) ; GraphicContentNode graphicContent = ( GraphicContentNode ) child ; graphicContent . setParentGraphicContext ( createGraphicContext ( ) ) ; if ( child instanceof GroupNode ) { if ( isInsideScaleGrid ( ) ) { throw new FXGException ( child . getStartLine ( ) , child . getStartColumn ( ) , "InvalidScaleGridGroupChild" ) ; } } children . add ( graphicContent ) ; } else { super . addChild ( child ) ; } }
adds an fxg child node to this group node .
