public void provideHighlightingFor(XtextResource resource,
			IHighlightedPositionAcceptor acceptor) {

		if (resource == null || resource.getParseResult() == null)
			return;

		INode root = resource.getParseResult().getRootNode();
		BidiTreeIterator<INode> iterator = root.getAsTreeIterable().iterator();
		while (iterator.hasNext()) {
			INode node = iterator.next();
			if (node.getSemanticElement() instanceof ParameterDesc) {
				// What I want to have:
                                // if (pdesc.isUnselected() == true) { do something }
			}
		}
}