ivaynberg/select2 — pull request #644 by kfiku (2012-12-13 09:39:46+00:00)
Title: Update select2.js

jQuery("input#someId").attr("tabIndex") don't work well in new jQuery 1.8+.
When you try this on field that don't have tabIndex attr you get undefined
(but document.getElementById("someId").tabIndex returns '0').
This is why Select2 element onBlur stay whit attr tabindex='-1'
and you can't navigate form with 'tab' key.
This simple ' || 0' fix this bug.