Comment 2 for bug 334533

Yes, the FUSA behaves in a similar fashion. The odd part is after pressing escape and leaving the menu, you could tab out of the applet but the only members in the focus cycle is the applet before and after the fusa/indicator.

Tabbing through applets in the GNOME panel is inherently broken, even the main menu applet does not do a great job. It is hard to fix because each applet is it's own app that needs to respect the tab order. So after you add more than two applets to the panel you get weirdness, that is why bug #334544 is important.