JScrollBar - Issue when changing models

Question

Hey All-
Well, I've come up with another interesting question which I haven't been able to resolve myself.
Basically, I have a single view port which consists of a custom JPanel and (2) JScrollbar's. I then have multiple data and view models which are attached to each of these components. I then have a JList which has a list of all the Data/View Models. When a user selects one of the Data/View Models from the JList, that Data/View Model is attached to the JPanel and (2) JScrollbar's.
Overall, this method seems to be working fine. When I select a new Data/View Model, the JPanel and both JScrollbar's update as expected. What happens next is unexpected though. If I then try to scroll one of the JScrollbar's, it jumps from its correct position to the last scrolled to position.
Here is a scenario that might explain it better:
1. Select one specific view model (which is basically a BoundedRangeModel for this scenario).
2. Use the scrollbar and scroll to a value of 100 (keeping it simple).
3. Select a new view model which has a value of 50 - the scrollbar now updates so instead of being located at value 100, it is now located at value 50
4. Use the scrollbar to scroll to a new value - when clicking with the mouse on the scrollbar, the scrollbar jumps back to a value of 100 and does not move. You must click the scrollbar again to begin scrolling, yet it is only affecting the selected View/Model, and no other model.
I have gone through all the code for the JScrollbar and its setModel() function from the Java source and there doesn't seem to be any obvious reason why this would be happening. Its almost as if the Scrollbar is somehow remembering its last scrolled to value and then jumping to this the first time you try to scroll, despite it not matching the value or extent contained within the RangeModel.
Right now this is a minor annoyance, but I'm wondering if anyone else has experience this issue.
Thanks!

Answer 1

Well, I somehow didn't receive notice that someone had responded to this thread, so sorry for not replying back sooner.
I did some additional digging using a simple application (which I will post below), and I have determined that this only appears to affect the Java Version 6. I have created and run the following simple test application in Netbeans using Java 6 in both Windows and Linux and have had the exhibited result above, but running Eclipse and Java 5 it appears to work fine (I use the IDE's to control which version of Java I am running).
Here's the Code:
package scrollbartest;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.DefaultBoundedRangeModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollBar;
public class ScrollbarTest extends JFrame implements ActionListener {
    public JScrollBar               displayScrollBar;          
    public ScrollbarTest() {
            super();
            this.setTitle("Scrollbar Test");
            this.setLayout(new BorderLayout());
            this.setPreferredSize(new Dimension(500, 350));
            this.setSize(new Dimension(500, 350));
            this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            displayScrollBar = new JScrollBar();
            displayScrollBar.setOrientation(JScrollBar.HORIZONTAL);
            setModel();
            this.add(displayScrollBar, BorderLayout.NORTH);
            JButton updateButton = new JButton("Update Model");
            updateButton.addActionListener(this);
            updateButton.setVisible(true);
            this.add(updateButton, BorderLayout.SOUTH);
            this.pack();
    private void setModel() {
            DefaultBoundedRangeModel rangeModel = new DefaultBoundedRangeModel();
            rangeModel.setMinimum(0);
            rangeModel.setMaximum(100);
            rangeModel.setValue(0);
            rangeModel.setExtent(0);
            displayScrollBar.setModel(rangeModel);
    public static void main(String[] args) {
            ScrollbarTest app = new ScrollbarTest();
            app.setVisible(true);
    public void actionPerformed(ActionEvent arg0) {
            this.setModel();
}And here's how to recreate the problem:
1. Launch a Java application using the above as the main class.
2. Move the scrollbar to some location other than the starting point.
3. Click the "Update Model" button which should reset the scrollbar using a new model.
4. Attempt to click (once) on the scrollbar position.
At step 4, using Java 6, the scrollbar "jumps" back to the position where it was located before setting the new model. This does not appear to change the value of the new model, and it locks out any more motion of the scrollbar until you release the mouse button and press again. At this point, the scrollbar begins functioning properly, except that it is now starting at the old models value instead of the current models value (which remains 0 until you click and drag a second time).
Using Java 5, this program works exactly as expected. My thought is that somehow the Scrollbar is keeping a reference to the old model or its values even after the model has changed for one more iteration. It seems to be the only thing that makes sense.
In any case, any help is greatly appreciated.