JScrollPanel Problem

Question

I am trying to create a results page for some testing software. The page has a JScrollPanel that contains a JPanel. On that JPanel I am using a GridBagLayout so that I can present the Q#, question, correct answer, thier answer, and the next row down will contain an explination of my answer that is spanned across all 4 columns.
The problem is that when I do this I would like to force the JScrollPane to only be as wide as the screen and force it to streatch downward as much as is needed. However if I just let the layout managers take care of things the TextAreas continue to expand horizontally and are not forced into multiple lines. If I set a preferred area on the JPanel then I think I am getting pretty close to the result that I want however there are no scroll bars on the scrollpane. When When I force the scrollbars to show up they show up blank as if there is nothing up or down, but I can see that the there must be something both up and down as it will show me the middle range of questions on the screen and cut off the first couple and last couple of questions.
I have included the code below of what is happen when this form is created. I am not adverse to changing the layout if anyone has a suggestion of what might work better, but this seamed like the best layout to me.
Thanks in advance for any advice.
Jason
    public frmResults(frmBook book, Quiz q, Student user) {
        initComponents();
        GridBagConstraints gridBagConstraints;
        _quiz = q;
        _student = user;
        _bookForm = book;
        _bookForm.setVisible(false);
        int _rows = _quiz.get_maxSize();
        panHolder.setLayout(new GridBagLayout());
        //make sure that the area of the text is not wider than the screen
        Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
        int w = this.getSize().width;
        dim.width = (dim.width-w)/2;
        dim.height = 5000; //I have tried many diffrent things here to no avail.
        panHolder.setPreferredSize(dim);
        int _y = 0;
        //load form with all of the questions
        for (int i=1; i<_rows; i++){
            Question _tmp = _quiz.get_QuestionAt(i);
            //Label for Question Number
            JLabel lblNum = new JLabel(i + ". ");
            gridBagConstraints = new java.awt.GridBagConstraints();
            gridBagConstraints.fill = gridBagConstraints.BOTH;
            gridBagConstraints.anchor = gridBagConstraints.NORTHWEST;
            gridBagConstraints.insets = new Insets(1,1,1,1);
            gridBagConstraints.gridx = 0;
            gridBagConstraints.gridy = _y;   
            //gridBagConstraints.weightx = .05;
            panHolder.add(lblNum, gridBagConstraints);
            //label for question text
            JLabel lblQuestion = new JLabel(_tmp.getQuestion());
            gridBagConstraints.gridx = 1;
            gridBagConstraints.gridy = _y;
            gridBagConstraints.weightx = 1;
            panHolder.add(lblQuestion, gridBagConstraints);
            //text area to input aswer
            JTextArea _txtAns = new JTextArea();
            JTextArea _txtExplain= new JTextArea(_quiz.getExplination(i));
            JTextArea _txtGivenAns = new JTextArea();
            _txtAns.setLineWrap(true);
            _txtGivenAns.setLineWrap(true);
            _txtAns.setWrapStyleWord(true);
            _txtGivenAns.setWrapStyleWord(true);
            _txtExplain.setLineWrap(true);
            _txtExplain.setWrapStyleWord(true);
            String _ans = _quiz.getResult(i, _student.getId());
            _txtAns.setText(removeQuotes(_ans));
            //format answerGiven
            String _ansGiven = _quiz.getAnswerGiven(i, _student.getId());
            _txtGivenAns.setText(_ansGiven);
            //set correct colors
            if(_ans.equals("Correct")){
                _txtAns.setForeground(new java.awt.Color(0,128,0));
                _txtExplain.setForeground(new java.awt.Color(0,128,0));
            else{
                _txtAns.setForeground(java.awt.Color.red);
                _txtExplain.setForeground(java.awt.Color.red);
            //add txtAns
            gridBagConstraints.gridx = 2;
            gridBagConstraints.gridy = _y;      
            gridBagConstraints.weightx = 0;
            panHolder.add(_txtAns, gridBagConstraints);
            //add txtAnswerGiven
            gridBagConstraints.gridx = 3;
            gridBagConstraints.gridy = _y;      
            //gridBagConstraints.weightx = .1;
            panHolder.add(_txtGivenAns, gridBagConstraints);
            //on the next line give explination
            _y++;
            gridBagConstraints.gridy = _y;
            gridBagConstraints.gridx = 1;
            gridBagConstraints.gridwidth = 4;           
            panHolder.add(_txtExplain, gridBagConstraints);
            _y++;
        this.setExtendedState(Frame.MAXIMIZED_BOTH);     
        dim.height = panHolder.getHeight();
        jScrollPane1.setMaximumSize(dim);
        jScrollPane1.setPreferredSize(dim);
        jScrollPane1.getViewport().setPreferredSize(dim);
        pack();
        panHolder.revalidate();
        jScrollPane1.revalidate();
        jScrollPane1.getViewport().revalidate();
    }

Answer 1

Actually in the example I posted panHolder is the panel that is inside of the scrollpane. panHolder is the one that I am attempting to tweak. However I have also tried tweaking the size of the scroll pane in order to solve the problem with no luck.
Essentialy what I want to do is force the scrollpane to not be larger than the screen. However it seams that no matter what I try to set prefered size on it causes the scrollpane to think that it should not scroll anywhere.
I will try to put together an example this afternoon to better demonstrate what is going on.
Thanks for the quick reply.
Jason