public IRenderingElement generate(IAtomContainer ac, RendererModel model) {
JChemPaintRendererModel jcpModel = (JChemPaintRendererModel) model;
if(model.getExternalSelectedPart()==null)
return new ElementGroup();
Color selectionColor = jcpModel.getExternalHighlightColor();
IChemObjectSelection selection = new AtomContainerSelection(model.getExternalSelectedPart());
return generate(selection, selectionColor, jcpModel);
}