Update the current "Empty" string to something that indicates it's an empty stack.
Created attachment 617537 [details] [diff] [review] empty stack
(In reply to Rob Campbell [:rc] (:robcee) from comment #2) > airport review!!! I claim Jet set status!
This patch was in a range which caused a Ts regression, so I backed out the whole range: https://hg.mozilla.org/mozilla-central/rev/24a6a53c714a Please reland after investigating and fixing the regression.