private boolean evaluateAvposClause(String str) {
		if (str == null || str.equals(""))
			return false;
		boolean on = str.equalsIgnoreCase("on");
		int n = model.getNumberOfParticles();
		if (n <= 0)
			return true;
		for (int k = 0; k < n; k++) {
			Particle p = model.getParticle(k);
			if (p.isSelected())
				p.setShowRMean(on);
		}
		view.repaint();
		notifyChange();
		return true;
	}