I'm getting a TypeError: elem.dispatchEvent is not a function using select2 in jquery using the wrapbootsrap pixel-admin theme.
It can be reproduced in firebug on the demo site via http://radiant-ocean-4606.herokuapp.com/forms-advanced.html
Firefox Version: 29.0.1 Firebug Version: 1.12.8
It's a similar error message to this question:
"element.dispatchEvent is not a function" js error caught in firebug of FF3.0
But the answer there doesn't help me as my site is all jquery (well as far as I know - I did somewhat accept the theme bundle as it came for the time being until I have time to really rip it apart and modify it in detail).
This was caused by changes to the browser, the solution was to stop using firebug. The features firebug offered are ubiquitous now!