Creating window groups on Netbeans Platform with Annotations

There's a related question
<http://stackoverflow.com/questions/9922179/creating-window-groups-on-netbeans-platform>
already
answered, but so much has changed since then with the use of annotations.

I'm registering TopComponents with annotations. For example:

@TopComponent.Registration(mode = "explorer", openAtStartup = false,
        roles = "Test Role")

Later I tried to open the group like this, as a test:

    WindowManager.getDefault().invokeWhenUIReady(() -> {
        WindowManager.getDefault().getRegistry().getOpened().stream()
                .forEach((tc) -> {
                    tc.close();
                });
        TopComponentGroup group
                = WindowManager.getDefault()
                .findTopComponentGroup("Test Role");
        if (group != null) {
            group.open();
        }
    });

All components are closed but nothing opens. It doesn't work, so obviously
some plumbing is missing.

Is this still the right way of doing it?

Is there a working example of this somewhere?

Question also in Stackoverflow
<http://stackoverflow.com/questions/36655361/creating-window-groups-on-netbeans-platform-with-annotations>
.