Scrollbar arrow buttons flickers when tumb is dragged eith up / down wards

I have a frame which contains two scrollbar , one in east & other in south , when i drag the tumb of the vertical scrollbar, the arrow button starts flickering.
Step to reproduce :
1) Run the attached program.
2) Drag the vertical scrollbar , observe that arrow buttons flickers.

I tested this on solaris 10 with mustang b98 , this does not happend when i pass -Dawt.toolkit=sun.awt.motif.MToolkit flag. I tested the same with b10 , 20 its working fine,but it starts flickering from b30 onwards. You can see a similar bug 6405707 which is got integrated in b83.


program
-----------
import java.awt.Scrollbar;

public class TestScrollBarFlickering extends java.awt.Frame{
private Scrollbar horizontal , vertical;
TestScrollBarFlickering(){
add("Center",new java.awt.Label("Scrollbar flickering test..." ,java.awt.Label.CENTER));
vertical = new Scrollbar(Scrollbar.VERTICAL, 0, 60, 0, 255);
vertical.setBackground(java.awt.Color.RED);
horizontal = new Scrollbar(Scrollbar.HORIZONTAL, 0, 60, 0, 255);
horizontal.setBackground(java.awt.Color.blue);
add("South",horizontal);
add("East",vertical);
setSize(400,400);
setVisible(true);
}
public static void main(String []args) {
new TestScrollBarFlickering();
}
}