Post Editor Page AJAX features not working properly

Hi folks

Before you show me the checklist on disabling plugins etc, I know that my problem is my theme. Its a bought theme, called Rework 1.2.0 by bitfade.

Background

The guys that set up the site (before I arrived on the scene), apparently did some customising, and didn’t use a child theme.

I scanned through last modified dates in the theme folder with FileZilla. By that measure, it looks like they only changed the header.php and footer.php.

Now I’m trying to get the support purchase key from these jokers. But in the meantime, I wondered if anyone here can point me in the right direction, as maybe the cause of the problem is simple.

The problem

The only problem with this theme is that the New Post and Edit Post pages have broken AJAX (only posts not pages).

When I click Add new category, Published on Edit, Status Edit, screen options, or instert media buttons/links, they do nothing.

Why I need help.

The site owner wants to migrate their blog to this installation, so the need for working posts has arisen. I just don’t know enough about what core files drive the ajax in the admin, to even understand this problem properly. A nudge in the right direction would go a long way for my knowledge.

Thanks in advance.