Comment 14 for bug 989588

I just experienced this in Raring. Only one X session running, so it didn't need that two-user scenario.

In this case, choosing Quit from the quicklist is having no effect. The update-manager process remains, and the Launcher and the alt-tab switcher still act as if there's an open window.

I notice now that window isn't attached to any of the virtual desktops. Maybe that's been true all along, and I've just realized it. I have the standard four virtual desktops, and on all of them, the Launcher shows the hollow or outline pip for "open, but not on this desktop."

Similarly, on all of the desktops, plain alt-tab doesn't show update-manager among the open windows. But Control-alt-tab, showing windows from all desktops, always includes it. Selecting it from this list has no effect, just like selecting it from the Launcher. Hm.