My theme background keeps disappearing for the middle and end of my form

When I'm editing it cancels my theme background for the form when you scroll down it's only a white screen. What am I doing wrong?

Here's how to fix it.

1. Open your form in the Advanced Designer https://www.jotform.com/build/80403981884161/design

2. Go to Background Image then check Fixed

3. Make sure to save the changes.

Alternatively, you can also fix it by injecting this CSS code to your form under CSS tab.

.supernova {background-attachment: fixed;}