so, in 1.22wmf8, there is a new collapsibleTabs.js ( https://bits.wikimedia.org/static-1.22wmf8/skins/vector/collapsibleTabs.js
in line 85 we ask "if ( $settings !== null )".
clearly, this is the wrong question. maybe
if ( typeof($settings) === "object" )
will work better.
as it is, when there is no data, "$setting" is undefined, and the test
$setting != null
returns true, because "null" and "undefined" are two different things.
this cause many things to fail, and in particular, unregistered users lose the "history" tab if they have JS enabled.
Whiteboard: gci2013 https://www.mediawiki.org/wiki/Google_Code-In#Candidate_tasks