If you set up a game with layered scrolling, where layers both paralax AND zoom at diferent rates, it works as expected with fullscreen mode set to off.
But if you then turn on fullscreen as leterbox-scaled it no longer works properly. Instead of layers set to scale-rate of zero (like for HUD layers or far BG layers like sky) taking the full screen, they stay at exactly 1 to 1 pixel ratio!
Here is a link to a construct2 file demonstarting the issue.
try it first as is and it works great..then change the fullscreen mode to letterbox-scaled and re-run it to se ethe HUD and far BG layers are now too small on screen.