From bug 27488 comment 72:
This bug is blocking deployment of the tabbed languages gadget on the English
Wiktionary ([[wikt:en:MediaWiki:Gadget-TabbedLanguages.js]]), which was
approved by vote a few months ago: [[wikt:en:Wiktionary:Votes/2012-10/Enabling
Tabbed Languages]]. It requires loading from the top for a number of reasons,
such as conditional running of CSS based on cookies.
He's referring to bug 27488, of course.
Splitting this issue out to a separate bug report, as whatever issue this gadget is hitting is obviously divergent (if not tangential). Possibly related to bug 27488, possibly not, and possibly solved by a different solution.