Function paint_app_owned_content 

pub fn paint_app_owned_content(
    scene: &mut Scene,
    transform: Affine,
    content_rect: Rect,
    theme: &Theme,
    draw: impl FnOnce(&mut Scene) -> bool,
) -> bool

Paint the framework-owned frame around one interactive app-owned surface (an app’s call or navigation card).

The frame is the one floating card (crate::widget::floating_surface::paint_card): its shape, shadow and edges, the same as a banner’s or the palette’s. Retained app content stands on the ordinary opaque Object ground inside it, not a translucent Panel material. The card’s shape clips every app paint, and its edge is drawn last so square app backgrounds cannot erase the frame. The native allocation remains transparent outside the card and its shadow; hosts allocate it with app_owned_content_window_rect.