One thing I don't get with CompositionLocals is that I need to "get" my local outside of my composable. i.e. Why do I have to do this?

val backHandler = LocalOnBackPressedDispatcherOwner.current
MyButton(
    clickEvent = { backHandler?.onBackPressedDispatcher?.onBackPressed() },

instead of this

MyButton(
    clickEvent = { LocalOnBackPressedDispatcherOwner.current?.onBackPressedDispatcher?.onBackPressed() },

It's the opposite. Your click event lambda is not a composable and therefore doesn't have access to the composition local. You are accessing the composition local from a composable in your example

ah. okay. visually it looks like im in my composable, but im not actually. it was all an illusion. cheers

Random trivia: If clickEvent was an inline function this would be possible since it’d consider itself to be inside the scope of your composable function