public void actionPerformed(ActionEvent event) {
		// JFrame frame = Universe.frameForEnvironment(environment);
		try {
			getExpression().asCheckedString();
		} catch (UnsupportedOperationException e) {
			JOptionPane.showMessageDialog(getEnvironment(), e.getMessage(),
					"Illegal Expression", JOptionPane.ERROR_MESSAGE);
			return;
		}
		ConvertToAutomatonPane pane = new ConvertToAutomatonPane(
				getEnvironment());
		getEnvironment().add(pane, "Convert RE to NFA", new CriticalTag() {
		});
		getEnvironment().setActive(pane);
	}