I've created a design with four elements:northwest, northeast, southeast, and southwest; each is on a separate level. I created the NW object first, the copied and rotated 180 deg to create the NE object and recolored. I then copied the NW and the NE objects and rotated them 180 deg to create the SE and SW objects. See below.
Now I'd like to add a background below all of them, but when I do, the NW object disappears. See below.
I don't have a clue as to why this is happening. I note that the little meatball next to the disappearing level is filled in, but it's empty for the other three levels. But I don't know what the two different meatball types mean. Each layer has a group layer and 26 sublayers. Some of the sublayers have different screen modes, and there is also a drop layer effect on one. They look identical to me, but with so many layers I might have missed something.
I'm using AI CS6 on a Dell computer.
Lyell <== throwing her hands in the air and shouting "Ah! Woe!"