[Plugin: Custom sidebars] Unregister_sidebar not working

I want to remove some extra sidebars (from my parent theme) from the list of sidebars on the Edit Page page. I used the unregister_sidebar function in my child theme’s functions.php file. But this only removed the names from the list of sidebars, not the actual dropdown menus, so it looks like “: dropdown bar.”

To test things out, I commented out the sidebar registrations from my parent theme’s functions.php file, and even that didn’t remove the dropdown menus.

Any ideas?

http://ww.wp.xz.cn/extend/plugins/custom-sidebars/