I've found other posts related to this, but none had a answer to my issue.
After updating to WP 3.4 my visual editor is broken.
Firebug reports this error
Failed to load: http://xxxxxx.com/wp-includes/js/tinymce/langs/pt.js
wp-tin...9-20805 (linha 1)
I've tried setting the theme to a default theme and it WORKS.
So, is there any way I can determine what's causing this in order to fix it?