Drawing into TabbedPane doesn't work

Question

Hi,
I want some stuff to draw distribute among several tabs which was originaly all in one panel.
This is basically what I did:
public Gui() {
        initComponents();
        this.setLocation(10, 10);
        this.setSize(800, 600);
        tabbedPane = new JTabbedPane();
        drawingPane = new DrawingPane();
        scroller = new JScrollPane();
        scroller.add(drawingPane);
        doSomeDrawing();
        this.add(tabbedPane, BorderLayout.CENTER);
    }But when I start the program the TabbedPane shows nothing which I can't quite understand. All I did was adding a tabbedPane to the hierarchy of components and putting into it what worked before flawlessly.
This is what the code looked like before I added the tabbedPane:
public Gui() {
        initComponents();
        this.setLocation(10, 10);
        this.setSize(800, 600);
        drawingPane = new DrawingPane();
        scroller = new JScrollPane();
        scroller.add(drawingPane);
        doSomeDrawing();
        this.add(scroller, BorderLayout.CENTER);
    }Any ideas why there is nothing to see?

Answer 1

Shit, I just shortened the example too much. I'm afraid some more code is necessary:
So this is the initiating method:
public Gui() {
        initComponents();
        dbCon = new DBConnector();
        objects = new LinkedList<Objects>();
        objects = dbCon.getAllObjects();
        this.setLocation(10, 10);
        this.setSize(800, 600);
        floors = dbCon.getFloorsName();
        drawingPane = new DrawingPane[floors.size()];
        scroller = new JScrollPane[floors.size()];
        windows = new JTabbedPane(JTabbedPane.TOP);
        for(int i = 0; i < floors.size(); i++) {
            drawingPane[i] = new DrawingPane();
            scroller[i] = new JScrollPane();
            scroller.add(drawingPane[i]);
windows.addTab(floors.get(i).toString(), scroller[i]);
for(int k = 0; k < scroller.length; k++) {
final int index = k;
scroller[k].getVerticalScrollBar().addAdjustmentListener(new AdjustmentListener() {
public void adjustmentValueChanged(AdjustmentEvent e) {
scroller[index].repaint();
scroller[index].getHorizontalScrollBar().addAdjustmentListener(new AdjustmentListener() {
public void adjustmentValueChanged(AdjustmentEvent e) {
scroller[index].repaint();
this.add(windows, BorderLayout.CENTER);
When the containing frame is visible I call a method like
   public void drawComponents(java.util.List<Objects> objectsToDraw) {
     java.util.List<Polygon> polygons = new LinkedList<Polygon>();
        for(int i = 0; i < objects.size(); i++) {
            drawingPane[0].addPolygon(new Polygon(...));
    }to add some stuff to draw but still nothing visible.
I hope this is enough code to find the problem. As I said, when I omit the tabbedPane and add the scollPane directly everything works fine.