Got the boolean set up and everything, added an environment texture under worlds, all was fine. Then I decided to delete the picture, and it disappeared leaving the grid behind except for in the window itself where the picture (a forest) is still there and behaving like it was before deletion. I deleted and created a new window, but no change.
assuming that you are using Eevee, you could try to delete lighting cache (in Render Properties - Indirect Lighting).
How did you delete the environment texture?
Can you remove everything but the window and upload the blend?
From the world menu, I think. Here’s the .blend file:
Thanks! You are in Material view and it is using a built-in HDRI (accidentally resembling your own environment texture) so the properties of reflective materials can be tweaked without loading an environment texture - this HDRI will not be used for rendering.
You can deactivate it and see your environment texture instead by using the dropdown menu to the right of the 4 viewport shading buttons and check “Scene World”.
I really appreciate it, but it sorta happened without me noticing. Cleared right up and I changed the alpha blend and now I have an image plane out behind it. Looks way better, less pixelated. The image is like 5000x3000 and I’m sure that was probably fixable, huh? Anyway, thank you so much!