FULL PRODUCT VERSION :
java version "1.8.0_151"
Java(TM) SE Runtime Environment (build 1.8.0_151-b12)
Java HotSpot(TM) Client VM (build 25.151-b12, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]


A DESCRIPTION OF THE PROBLEM :
I have a JScrollBar with extent equal to total range. It shouldn't display the thumb since
no scrolling is possible (Extent == Maximum - Minimum). And it doesn't unitil JScrollBar is resized to be longer than approximately 1000px. In this case a 1000px-long thumb is drawn.

I see this behaviour ONLY when I am using Nimbus L&F. It behaves similarily with JDK 8u131.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Create a JFrame frame with Nimbus Look and Feel, provide it with default BorderLayout. Place horizontal JScrollBar inside the frame with BorderLayout.CENTER position, set scrollbar model parameters to be "minimum == 0, maximum == 100, extent == 100".

Run the frame, when frame with scrollbar appears --- stretch it horizontally to be wider than 1200 px.


 

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
There shouldn't be visible thumb in scrollbar.
ACTUAL -
There is a thumb when the scrollbar is long enough.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import javax.swing.BoundedRangeModel;

public class NimbusFrame extends javax.swing.JFrame {

public NimbusFrame() {
initComponents();

BoundedRangeModel model = xScrollBar.getModel();
model.setMinimum(0);
model.setMaximum(100);
model.setExtent(100);

}

@SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        xScrollBar = new javax.swing.JScrollBar();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        xScrollBar.setOrientation(javax.swing.JScrollBar.HORIZONTAL);
        getContentPane().add(xScrollBar, java.awt.BorderLayout.CENTER);

        pack();
    }// </editor-fold>

public static void main(String args[]) {
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
}
catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(NimbusFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(NimbusFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(NimbusFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(NimbusFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
//</editor-fold>

/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
new NimbusFrame().setVisible(true);
}
});
}
                    
    private javax.swing.JScrollBar xScrollBar;
               
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Use another Look And Feel. Or manually disable the scrollBar when extent equals to total range.