A self-hiding child cannot hide its slot

Optional controls commonly hide themselves: no platform support, no permission, nothing to connect to — render nothing. That is correct and it is not enough. A caller that gave the control a container, a weight or a divider still draws all three around an empty box.

The component's own contract has to say so, in the same file that declares it:

// adapted
/**
 * Whether [OptionalControl] would render anything. Layouts that give it a container of its own
 * must hide the container too when this is false — the control hides itself, but it cannot hide
 * a wrapper it does not own.
 */
expect fun isOptionalControlAvailable(): Boolean

Traps