Why does setOpaque(false) on Mac interfere with functionality of JSlider?

Question

Hello, here is an SSCCE with a slider that works normally on my PC:
import javax.swing.*;
public class Foobar extends JApplet
     public  void init()
          JPanel panel = new JPanel();
          panel.setOpaque(false);
          panel.add(new JSlider());
          setContentPane(panel); 
}But on my sister's Mac, the slider functionality is broken: one cannot drag the thumb with the mouse. To move the thumb, she has to click on the rail. If I comment out the setOpaque(false) call, then everything works fine.
I need that setOpaque call and I want the program to work both on Mac and PC. Why does it break on the Mac and how to fix it? Thank you for your insight. Mark

Answer 1

So then you haven't actually ran that SSCCE on a MAC then? No, no, she ran it on her Mac, my sis. I asked her to run it several times, and she definitely cannot move the thumb. Now, if I comment out the setOpaque(false), then she can move it all right.
But, I found a workaround. I did not realize that before, that Apple actually does include the "cross-platform" look and feel, not only their own Aqua. On the Sun website, it sort of implies that Apple only has Aqua, but on Apple website, I found they also support the cross-platform look.
And voila, I changed to the cross-platform, and now, everything works. Not only the sliders in non-opaque panels, but I had also a HUGE number of other problems getting my app to work on the Mac, and now, with the cross-platform look, they all disappeared!!
Thank you.
Mark