I have an issue I've just encountered. In Be 3.8 I created some sidebars. Attached one of the sidebars to a page. Now I want to go to /wp-admin/widgets.php. At this point something already doesn't seem right, as in the WP dashboard in the top left corner there is a white gap between the WP logo and the Dashboard link. This white gap I can only see on this page. But the issue itself is the following:
When I add anything to a custom created sidebar and save it, it will work fine. But when I open the /wp-admin/widgets.php again it becomes empty again.
This only affects custom created sidebars - the footer for example works fine.