On Theme Option screen, Overall Box Layout, Theme Chooser, picking the any new theme (such as “Round Blue”), the lightbox will show “Loading 0/106” and progress squares moving, but nothing ever completes. Sample screen attached. I’m hosted by “WPEngine”.
I have tried deactivating plugins and it did not fix the problem. 🙁
Indeed, I was able to replicate the issue. It is related to the last weeks update, where I made a tiny mistake in a different file, and didn’t notice this breaking it.
I’m attaching an early access hotfix release to this reply, please de-activate, delete and install this one instead via the plugin manager. All your options will remain unchanged.