Hi there, of late, the ‘add media’ and even ‘screen options’ buttons on my Posts and Page edit pages do not work. I disabled all my plugins, no luck either. However, when I switched themes to Twenty Fourteen, things were back to normal (just that my site sucked)
Since I’m on a child theme, I tried reverting to the parent theme (stopped using the child) and the problem persists. I’ve tried this on Chrome and IE11 already.