MouseArea in MouseArea in QQuickWidget leaks the inner mouse events to the root widget window

In QQuickWidget, If one MouseArea overlaps another MouseArea, clicking the overlapping area will leak the mouse event to the root widget window. This does not happen in Qt 5.15.9.

In the example, click the red rectangle where there are two overlapping MouseAreas and see the mouse event is leaked to the main window. Click the green rectangle where there is only one MouseArea, and the mouse event is not leaked.

See also: https://invent.kde.org/plasma/systemsettings/-/merge_requests/237