Empty sections cannot be added to or deleted

I have a header with four empty sections in it. I deleted their contents and they became invisible. Since they have no presence on the screen I can’t add anything to them. I can see them in the layers view, and rearrange them, but can’t drag contents to them or delete them.

Because I’ve reached the limit of sections (apparently) I cannot add more. I have no way to delete the empty sections. So I’m stuck. The only way I’ll be able to use a section is to uninstall your plugin, delete its data, reinstall it and start over.

I also looked at it in phpMyAdmin, but the data are blobs so I can’t fix it that way.