First. Thanks for this must-for-ever-have extension for WordPress. Should be part of the core!
Now the problem: The button of the “File” (or “Image”) field type is not working. When hovering on it, my browser should display the link, but it displays “go to # on this page”.
Then, clicking the button doesn’t do anything.
I thinks its JS error. Just by loading the post editor, my web inspector tells this: