I have a problem that has completely baffled me. I had a sidebar with an id of 'after-content-ad'. It contained a text widget that was displaying correctly on the front end. I needed to make some changes so I attempted to edit the contents of the text widget on the widgets admin page. The sidebar area was completely empty. The sidebar description did not even show.
I tried several things to resolve the issue including clearing the text widget serialized content drom the wp_options table. This obviously removed the front end display but did not fix the admin page problem. I also disabled all of the plugins. By the way, all other sidebars work just fine.
As a work around, I copied the original code and just changed the id of the sidebar by one character (after-content-ad1) and it works fine. As soon as I change the id back to the original, it fails.
The only two places in the database that I know of that store information regarding sidebars is serialized data in sidebars_widgets and the serialize data in the various widget types, both in the wp_options table. they both seem fine.
I think I may have caused the problem by inadvertently registering the same widget id twice in my functions file. I have since fixed this problem so I don't understand why the issue still exists.
I have no cache plugins installed and I cleared my browser cache.
By the way, I am using Genesis with a customized version of their Magazine child theme.
I obviously have a work-around but I would really like to understand the problem.
Thanks for your help!