I had some strange behaviour with the jQuery verion of tinyMCE (3.4.6). Basically I was integrating the chosen library (which is build as a jQuery plugin), but it seems the $.attr(‘id’) from within chosen.js was returning a JavaScript element reference instead of the value of the “id” field.
Some basic tracing showed the strange error:
The solution for me was moving to tinyMCE 3.5.4.1 (and jQuery 1.7.2, previously I was on 1.6.4). All good now, just thought I’d throw up a quick post if anyone was being caught by this.