Internal: b/143100923

When a Stack contains MyWidget inside of a Positioned.

    Stack(
      overflow: Overflow.visible,
      children: [
        Positioned(
        top: -50.0,
        child: MyWidget(),
      )],
    );

Since overflow is Overflow.visible, MyWidget displays outside of the Stack. However, it doesn't accept gestures in the overflowed area. I have no idea if it's easy, difficult or downright impossible to make this change, but I can think of a gazillion use cases for that, which at the moment must be satisfied by using the much more complex Overlay, or some Stack tricks.

And in case it's impossible to make this change, then at least the documentation should clearly state that overflowed content can't receive gestures.

Also, see: https://stackoverflow.com/questions/51366761/in-flutter-how-can-a-positioned-widget-feel-taps-outside-of-its-parent-stack-ar