Using the provided starter content these steps will replicate the issue:
- go to background > image - add a background image to site.
- go to widgets > footer column 3 > Custom HTML, edit the custom html content to trigger a partial refresh (you can just add a space or something to some text to trigger).
- go back to background > image
The result is that all controls are displayed (pattern/color and image controls), and haven't been filtered out by the tab as it should (only background image in this case):

