Comment 73 for bug 940631

(In reply to Kai Engert (:KaiE:) from comment #59)
> That code would have to prevent the race, by detecting if the first prompt has already been opened, and all consecutive requests would have to be put on hold, as long as the first prompt is shown or retrying. After the prompt has been completed or canceled, all queued up requests to unlock must be signaled to continue.

I found that this approach is unlikely to work, as described in bug 177175 comment 384 (which also describes an alternative approach, which is more work, and requires changes to login manager).