Steps to reproduce:

1. Create a JFrame with a JToolBar
2. Add JToggleButtons to the JToolBar
3. Click on the buttons

Expected: the toggle button looks pressed or armed and have the special look & feel for tool bar buttons on macOS as they look in pretty much every Apple preferences pane on macOS (sample from the Mail app attached as screenshot).

Obtained: The pressed toggle button cannot be distinguished from others

This issue *is not yet* fixed in openjdk 15-ea 2020-09-15.

Here's some sample code (resulting screenshot attached) that create such a frame with a toolbar with JToggleButtons. To contrast, the sample code also contains some JToggleButtons added to a regular button.

import javax.swing.*;
import java.awt.*;

public class PrefToggles {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                try {
                    // do this as the very first thing, to make sure, whatever we read as defaults are actually platform defaults
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });

        final JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        final JToolBar toolBar = new JToolBar();
        toolBar.setFloatable(false);
        final Icon icon = new Icon() {
            @Override
            public void paintIcon(final Component c, final Graphics g, final int x, final int y) {
                g.fillOval(x, y, 32, 32);
            }

            @Override
            public int getIconWidth() {
                return 32;
            }

            @Override
            public int getIconHeight() {
                return 32;
            }
        };
        toolBar.add(new JToggleButton("One", icon));
        toolBar.add(new JToggleButton("Two", icon));
        frame.getContentPane().add(toolBar, BorderLayout.NORTH);
        final JPanel regularPanel = new JPanel();
        regularPanel.add(new JToggleButton("Three", icon));
        regularPanel.add(new JToggleButton("Four", icon));
        frame.getContentPane().add(regularPanel, BorderLayout.CENTER);
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                frame.setBounds(500, 500, 500, 200);
                frame.setVisible(true);
            }
        });
    }
}


Hint: The special border for toolbar toggle buttons is set in com.apple.laf.AquaButtonUI#setThemeBorder(...) using com.apple.laf.AquaButtonUI#isOnToolbar(...). But for some reason the correct graphics are not painted as expected.

This bug has been reported before (https://bugs.openjdk.java.net/browse/JDK-8224712), but has unfortunately not been addressed properly.