I don't know when I have to use crop or scale mode. It's weird when I get different results from layout. Only in Letterbox mode can preserve the position of HUD regardless of screen size, isn't it? Why CocoonJS doesn't support letterbox mode?
Yes, and it's not about camera moving or something. It's about display size. If someone put HUD or sprites in the place, watching the window size line, that means he or she wants screen to show them in THAT place, not cropped by display border. In browser, you can deal it with letterbox mode, but in CocoonJS, you can't. And I wonder what can I do with it.
The anchor behavior pins the sprite to that spot on your viewport. So it will stay in that spot. So if you pin it to the upper right corner, it should stay near the upper right corner no matter what else is going on if HUD is set to no parallax and on its own layer.