Comment 5 for bug 343618

Notification bubbles appear in the corner because they were (and, in Notify OSD, still are) intended to be used for notifications, i.e. telling you about things that happened unprompted. They were then misused for things like this that happen as a direct result of user action ("Eject" or "Unmount" in this case), and therefore don't have any particular reason to appear in the corner. Where we're replacing a notification bubble with a custom alert box, that shouldn't appear in the corner either. As with an alert box, you can move it or bring another window in front of it; and since it's a progress window, you can minimize it too.