is
Picking flows through the inner per-window surfaceImage (it owns the surface texture drawable the user actually clicks on), so propagate the outer's pick state onto every window's SurfaceImage. Without this, a click on the viewshed overlay returns the internal SurfaceImage as the picked userObject instead of this ViewshedSightline. The outer's render() gate already suppresses pick rendering when isPickEnabled is false, but we still mirror the flag onto each SurfaceImage for defence in depth.