I have the impression that site builders/admins use a different theme for the admin backend. How cool would it be to be able to preview the changes made to the layout/blocks of the frontend theme as they make changes in the UI?
Here's how Craft CMS does it with their WYSIWYG editor:

We already have a live preview in place for views and another for the color-picker, so perhaps we can abstract and reuse that.
GitHub Issue #:
986
Recent comments
So the implication is that another module is causing the trouble. Now for the slow process of elimination... Sounds plausible. And good luck with digging...
How to troubleshoot interactive image cropping modules?
I’ve just set up a clean install in MAMP and Focal Point works fine. *sighs So the implication is that another module is causing the trouble. Now for the slow process of elimination...
How to troubleshoot interactive image cropping modules?
Here’s the edit screen with the Focal Point instructions below: If I click on the Preview link, I get this: And no errors in the console.
How to troubleshoot interactive image cropping modules?