Hello Elliot,
I think there is a problem with the drag, see the video:
Video
There can be many reasons for that… Do you have any experience in debugging possible javascript etc. errors?
My wild guess is that your theme or some plugin(s) are loading js code that causes a conflict and prevents the functionality.
Have you had the same issue on some other websites? Or is this the only time you are seeing this?
No plugin activated on this installation. WP debug mode is set to TRUE. All work fine but i’ve this errors: