An addon could do it, but you would have to effectively re-parent the Reticle to new TopLevelControl when enabled and hide GuiRoot, then reverse that switch when disabled.
Very doable.
Slightly risky.
I'll consider adding it to Full Immersion if it works well when I get time to test it.
What if you approached it from the other direction? Choose the UI elements you don't want to see, and just hide those.
I haven't tried Wykkyd's Full Immersion addon, but it sounds like something you might like. I use, and have read, a lot of his other stuff. He writes good code.
Thanks, i just got clarity addon to hide certain elements, but its not easily togglable, i have to search a.list of what i want to choose then reloadui which is a pain but it does the trick.
would be good to select a check list of what i want to hide, and toggle it via keybind?