The browser id login tries to disappear when you traverse to other sites. Ex: If you click on another tab it will disappear. If you click in the location bar, the browser id login will disappear. However if you use Ctrl+ L, the keyboard shortcut. It doesn't disappear. This allows the browserid login to be visible even when looking at other sites.
A Pivotal Tracker story has been created for this Bug: http://www.pivotaltracker.com/story/show/24808757
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