* for a menu you want this:

 ```
   const Qt::Edge sideEdge = q->isRightToLeft()  ? Qt::LeftEdge : Qt::RightEdge;
   q->windowHandle()->setProperty("_q_waylandPopupAnchor", QVariant::fromValue<Qt::Edges>(Qt::TopEdge | sideEdge));
   q->windowHandle()->setProperty("_q_waylandPopupGravity", QVariant::fromValue<Qt::Edges>(Qt::BottomEdge | sideEdge));
```