Good Morning,
I am one of the individuals experiencing the PageBuilder glitch after upgrading to Wordpress 3.6, I also added the .ui-widget-overlay{z-index:80 !important} code to /framework/post-type/style.css. However, that did not solve the issue as the lightbox editor is still "greyed out" and I am only able to tab between the title, CSS and content sections but not of the buttons work (i.e. cannot select HTML, Save, or use any of the text editing tools). This is a major issue since I have a client trying to make edits and he is unable to do so. I look forward to a timely resolution to this issue as I would prefer having to revert back to Wordpress 3.5, thanks!