How do I remove the new background and floor from the Material Editor preview in 4.18?

Thank you! But it looks like there’s a bug.

When I open “Preview Scene Settings” both the floor and the environment sphere disappear. They’re already unchecked, and the editor remembers them unchecked. It just forgets to see if they’re unchecked or not when opening any new material, and I have to manually open the “Preview Scene Settings” each time, for every material, and at every editor restart. Hotfix incoming?