PLAF cannot change button color

We have a program that can switch between day (high contrast) and night (low contrast) modes. This is done by changing the appearance on the fly. It works for almost all components, but some ignore background color changes. In particular, I noticed that buttons, comboboxes and table headers ignore changes in PLAF.

Here's a sample program with a button. Am I doing something wrong? Does it somehow depend on the OS? (I'm on OSX)

import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.plaf.ColorUIResource;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;

public class Demo extends JFrame {
   public static void main(String[] args) {
      new Demo();
   }

   public Demo() {
      setTitle("PLAF button test");
      final Demo thisWindow = this;
      final JButton button = new JButton("Click me!");
      button.addActionListener(new ActionListener() {
         @Override
         public void actionPerformed(ActionEvent e) {
            Color curColor = UIManager.getColor("Button.background");
            ColorUIResource targetColor;
            if (curColor.equals(new Color(32, 32, 32))) {
               targetColor = new ColorUIResource(192, 192, 192);
            }
            else {
               targetColor = new ColorUIResource(32, 32, 32);
            }
            System.out.println("Setting new color to " + targetColor +
               " because old color was " + curColor);
            UIManager.put("Button.background", targetColor);
            SwingUtilities.updateComponentTreeUI(thisWindow);
         }
      });
      add(button);
      setMinimumSize(new java.awt.Dimension(200, 200));
      setVisible(true);
   }
}

      

        
        
        
      

    

And here is the result I get when I run this program and click the button:

Setting a new color to javax.swing.plaf.ColorUIRsource [r = 32, g = 32, b = 32] because the old color was com.apple.laf.AquaImageFactory $ SystemColorProxy [r = 238, g = 238, b = 238 ]

Setting a new color to javax.swing.plaf.ColorUIResource [r = 192, g = 192, b = 192] because the old color was javax.swing.plaf.ColorUIResource [r = 32, g = 32, b = 32]

Setting a new color to javax.swing.plaf.ColorUIResource [r = 32, g = 32, b = 32] because the old color was javax.swing.plaf.ColorUIResource [r = 192, g = 192, b = 192]

Setting a new color to javax.swing.plaf.ColorUIResource [r = 192, g = 192, b = 192] because the old color was javax.swing.plaf.ColorUIResource [r = 32, g = 32, b = 32]

So, the UIManager thinks that the color changes, but the visible color on the screen does not change.

Any advice is appreciated. Thank you for your time.