public boolean isDone() {
		int toDo = pToT.size() - alreadyDone.size();
		String message = toDo == 0 ? "The conversion is finished!" : toDo
				+ " more transition" + (toDo == 1 ? "" : "s")
				+ " must be added.";
		javax.swing.JOptionPane.showMessageDialog(parent, message);

		return toDo == 0;
	}