private void addItem(Production item) {
		if (restricted != null && !restricted.contains(item)) {
			JOptionPane.showMessageDialog(parent, item.toString()
					+ " is not part of the set.", "Item not Desirable",
					JOptionPane.ERROR_MESSAGE);
			return;
		}
		if (alreadyChosen.contains(item)) {
			JOptionPane.showMessageDialog(parent, item.toString()
					+ " is already chosen.", "Item Already Chosen",
					JOptionPane.ERROR_MESSAGE);
			return;
		}
		alreadyChosen.add(item);
		choiceTable.getGrammarModel().addProduction(item);
	}