public void rendererChanged(final RendererChangeEvent event) {
final Plot parent = this.getParent();
if (parent != null) {
if (parent instanceof RendererChangeListener) {
final RendererChangeListener rcl = (RendererChangeListener) parent;
rcl.rendererChanged(event);
} else {
// this should never happen with the existing code, but throw
// an exception in case future changes make it possible...
throw new RuntimeException(
"The renderer has changed and I don't know what to do!");