Edge Browser freezes indefinitely when launching one Browser from another via a BrowserFunction

Summary

Edge Browser freezes indefinitely when launching one Browser ("child" Browser) from another ("parent" Browser) via a BrowserFunction using Display#syncExec to create the child Browser. The same behavior is not exhibited when the child Browser is created within a Display#asyncExec call.

Also want to note when SWT gets into this waiting state, closing the window does not kill the process. The process will run until killed manually.

Code To Reproduce

package snippets;

import org.eclipse.swt.SWT;
import org.eclipse.swt.browser.Browser;
import org.eclipse.swt.browser.BrowserFunction;
import org.eclipse.swt.browser.ProgressAdapter;
import org.eclipse.swt.browser.ProgressEvent;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

@SuppressWarnings({ "javadoc", "nls" })
public class EdgeSnippet
{
    private static Display display;
    private static Shell shell;

    public static void main(String[] args)
    {
        display = new Display();
        shell = new Shell(display);
        shell.setLayout(new FillLayout());

        Browser parentBrowser = new Browser(shell, SWT.EDGE);
        parentBrowser.setText("<!DOCTYPE html> \n"
                + "<html>\n"
                + "<head> \n"
                + "</head> \n"
                + "<body>\n"
                + "   <button onclick = \"openChildBrowser()\"> Open child browser </button> \n"
                + "   <p> \n"
                + "      <div id = \"result\"> </div> \n"
                + "   </p> \n"
                + "</body> \n"
                + "</html>");
        parentBrowser.addProgressListener(new ProgressAdapter()
        {
            @Override
            public void completed(ProgressEvent event)
            {
                new OpenChildBrowserBrowserFunction(parentBrowser, "openChildBrowser");
            }
        });

        shell.pack();
        shell.open();
        while (!shell.isDisposed())
        {
            if (!display.readAndDispatch())
            {
                display.sleep();
            }
        }
        display.dispose();
    }

    private static class OpenChildBrowserBrowserFunction extends BrowserFunction
    {
        public OpenChildBrowserBrowserFunction(Browser browser, String name)
        {
            super(browser, name);
        }

        @Override
        public Object function(Object[] arguments)
        {
            // If the following line is changed to asyncExec, the code executes just fine
            display.syncExec(() ->
            {
                System.out.println("Opening Child Shell");

                Shell childShell = new Shell(shell);
                childShell.setLayout(new FillLayout());
                childShell.setText("Child Browser");

                Browser childBrowser = new Browser(childShell, SWT.EDGE);
                childBrowser.setText("<!DOCTYPE html> \n"
                        + "<html>\n"
                        + "<head> \n"
                        + "</head> \n"
                        + "<body>\n"
                        + "   <p> \n"
                        + "      Child browser"
                        + "   </p> \n"
                        + "</body> \n"
                        + "</html>");

                childShell.pack();
                childShell.open();
            });
            return null;
        }
    }
}

Stack Trace

SWT waits indefinitely on the org.eclipse.swt.internal.win32.OS.WaitMessage call below:

org.eclipse.swt.internal.win32.OS.WaitMessage(Native Method)
org.eclipse.swt.widgets.Display.sleep(Display.java:4752)
org.eclipse.swt.browser.Edge.callAndWait(Edge.java:227)
org.eclipse.swt.browser.Edge.create(Edge.java:342)
org.eclipse.swt.browser.Browser.<init>(Browser.java:99)
snippets.EdgeSnippet$OpenChildBrowserBrowserFunction.lambda$0(EdgeSnippet.java:76)
org.eclipse.swt.widgets.Synchronizer.syncExec(Synchronizer.java:183)
org.eclipse.swt.widgets.Display.syncExec(Display.java:4785)
snippets.EdgeSnippet$OpenChildBrowserBrowserFunction.function(EdgeSnippet.java:68)
org.eclipse.swt.browser.Edge.handleCallJava(Edge.java:543)
org.eclipse.swt.internal.win32.OS.DispatchMessage(Native Method)
org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3640)
snippets.EdgeSnippet.main(EdgeSnippet.java:49)

Expected behavior The child Browser opens successfully.

Environment:

Select the platform(s) on which the behavior is seen:
- [ ] All OS
- [x] Windows
- [ ] Linux
- [ ] macOS
Additional OS info (e.g. OS version, Linux Desktop, etc) Windows 10, also observed on Windows Server 2016
JRE/JDK version JDK 11.0.14.1

Version since SWT 3.117-Current (3.123 at the time of writing this)

Known Workarounds

Make either the parent, child, or both Browser(s) non-Edge Browser(s)
Use Display#asyncExec instead of Display#syncExec to create the child Browser

eclipse-platform / eclipse.platform.swt