showsPreview property
iOS: whether a long press lifts a preview of child, as a system context menu does in Photos or Messages: the child rises above the blurred screen with the menu beside it, and settles back when the menu closes (#138). Off, the menu opens at the pressed point with nothing lifted. macOS menus have no preview.
A menu opened from code is a button menu, which UIKit never shows with
a preview, so with this on a clear native view with a
UIContextMenuInteraction is laid over the child, and the child is
drawn to an image when the finger goes down. A tap still reaches the
child; a long press goes to the native view. Each such region is a
platform view, so in a long list keep it to the rows that need it.
Implementation
final bool showsPreview;