Embedding swing in JavaFX which is also embedded in Swing, causing extra COMPONENT_SHOWN events

OK, this is a weird one.

I'm embedding swing components in a JavaFX component which in turn is embedded in a Swing GUI and for some reason it is causing my combo boxes to not work.

I know that the first answers I'm going to get are "For the love of all that is good in this universe, why would you ever do anything like this". If that's your initial response, then you are not wrong, but still I would like to understand what is going on. To briefly answer why I am doing this at all, we have a large amount of swing code in our toolset, but we've started using JavaFX for any new GUI components. Sometimes those JavaFX components will use some of our older swing components inside them since we often don't have the time/budget to re-write everything we'd like to update. So in this minimum reproducible example, it would be easy to just get rid of the internal swing component, but the actual software I'm interested in is much larger.

Here is my minimum reproducible example:

public class BadComboBox {
    
    public static void main(String[] args) {
        SwingUtilities.invokeLater(BadComboBox::createGUI);
    }
    
    private static void createGUI() {
        JFrame frame = new JFrame();
        JTabbedPane tabPane = new JTabbedPane();
        
        JComboBox<String> comboBox = new JComboBox<>();
        comboBox.addItem("one");
        comboBox.addItem("two");
        
        tabPane.add("1", getFxPanelWithEmbeddedSwing());
        tabPane.add("2", comboBox);
        
        frame.add(tabPane);
        frame.setVisible(true);
        frame.setSize(300, 100);
    }
    
    private static JFXPanel getFxPanelWithEmbeddedSwing() {
        JFXPanel jfxPaneWithEmbeddedSwing = new JFXPanel();
        Platform.runLater(() -> {
            Scene scene = new Scene(new PaneWithSwingNode());
            jfxPaneWithEmbeddedSwing.setScene(scene);
        });
        return jfxPaneWithEmbeddedSwing;
    }
	
	private static class PaneWithSwingNode extends Pane {
	    
	    public PaneWithSwingNode() {
	        SwingNode swingNode = new SwingNode();
	        this.getChildren().add(swingNode);
	        SwingUtilities.invokeLater(() -> swingNode.setContent(new JPanel()));               
	    }
	}
}

As you can see I've got a tabbed pane with two tabs. The first contains a JavFX pane which contains an embedded swing node. If you launch the program, click on the second tab and then click on the dropdown button on the combo box, it will appear to not expand. In actuality, it expands and then immediately collapses again.

I did some debugging that involved stepping through the bowels of the AWT event dispatch code and found that for whatever reason, a COMPONENT_SHOWN event is getting triggered, which ends up calling the combo box's ancestorAdded listener, which hides the combo box popup.

If I remove the line that adds the SwingNode to the JavaFX pane, then the combo box will work just fine.