protected String addMGameFeatures() 
	{
		myMDisplay = new JTextField(10);
	    ((JTextField)myMDisplay).addActionListener(new ActionListener()
            {
                public void actionPerformed (ActionEvent ev)
                {
                    try
                    {
                        reset();
                        int m = Integer.parseInt(ev.getActionCommand());
                        if(!(m  >= myLemma.getRange()[0] && m <= myLemma.getRange()[1]))
                            throw new NumberFormatException();
                        myLemma.setM(m);
                        stages[2].setVisible(true);
                        stages[3].setVisible(true);                      
                        mEnteredReset();
                        /*
                         * If this is has only one case, myCases will not be initialized
                         * so we check for null.
                         */
                        if(myCases != null)
                            myCases.setListButtonEnabled(true);
                    }
                    catch(NumberFormatException e)
                    {
                        //Something other than a positive integer was entered.
                        String error = "Please enter a positive integer in range [" +
                            myLemma.getRange()[0] + ", " + myLemma.getRange()[1] + "] for best results.";
                        myMDisplay.selectAll();
                        stageMessages[1].setText(error);
                    }
                }
            });
	    return new String(PROMPT_M);
	}