Missing Layers

I am teaching 7th graders how to make a platformer game in C3. One of my students has lost their layers (game and background). The layers window is showing but the layers are gone. We can still see about half of her objects in her Level One Layout. Does anyone have suggestions for how to recover her layers?

I'd assume they were deleted by accident, and try Ctrl+Z. If that doesn't work and especially if the file has been saved... they're gone.

Unless you did set up the automatic backup function in Construct, in which case you can check for a backup.

If that wasn't set up, I guess you can turn this into a lesson on the importance of keeping backups.