public void actionPerformed(ActionEvent e) {
		LSystem lsystem = getEnvironment().getLSystem();

		if (lsystem.getAxiom().size() == 0) {
			JOptionPane.showMessageDialog(getEnvironment(),
					"The axiom must have one or more symbols.",
					"Nonempty Axiom Required", JOptionPane.ERROR_MESSAGE);
			return;
		}

		try {
			DisplayPane pane = new DisplayPane(lsystem);
			getEnvironment().add(pane, "L-S Render", new CriticalTag() {
			});
			getEnvironment().setActive(pane);
		} catch (NoClassDefFoundError ex) {
			JOptionPane
					.showMessageDialog(
							getEnvironment(),
							"Sorry, but this uses features requiring Java 1.4 or later!",
							"JVM too primitive", JOptionPane.ERROR_MESSAGE);
			return;
		}
	}