I was working on my game yesterday, and in the middle of working on stuff I realized that objects in the background layer can’t be communicated to via the message block.
My suggestion is to simply let game and UI layer objects also communicate with objects in the background layer.
It makes stuff less confusing, and helps people make more intricate games. That is all, thank you!
You can make your own background objects in the game layer by making it have a display order of 1 while everything else is 2 or higher. That way you can have messages be sent to it and add code.
Currently I don’t think background objects have the ability to add code or be used for anything other than graphics. But I do believe grazer already had plans to change that.
You can do almost everything with background layer objects, except collisions. Also, I would absolutely just put the background on the main layer but I’m worried it’ll make the game harder to work on. I’ll probably just do that for now though, thank you 
Game Layer objects can’t use parallax and can’t be repeated by the camera