How to hide background image?

[John37]

Please does anyone know how can I hide the background image? The Hide background image and the Delete background image menu items are both greyed out, and don't work.

[Puybaret]

You must have created some levels, right?
Each level can have its own background image and when a level is at the same elevation as an other one, it will display the same background image. So just select the previous level and on that level, you'll be able to hide its background image.

[John37]

You are right (of course). Thank you very much for your patience and help.