ivaynberg/select2 — pull request #1728 by corinnaerin (2013-09-17 20:46:58+00:00)
Title: Compatibility with jQuery 1.9 +

removeAttr("disabled') is no longer correct as of version 1.9 of jQuery. Should use prop("disabled", false) instead.

See http://jquery.com/upgrade-guide/1.9/#attr-versus-prop-