QGraphicsView with Qt::WA_TranslucentBackground + Qt::WindowStaysOnTopHint no longer let mouse events pass through the background

Context : Migrating code from Qt5.5 to Qt 5.13

The same code that still works on Linux and Windows no longer works on Mac (it worked with Qt 5.5) : 

mTransparentDrawingView->setAttribute(Qt::WA_TranslucentBackground, true);
#ifdef Q_OS_OSX
    mTransparentDrawingView->setAttribute(Qt::WA_MacNoShadow, true);
#endif
mTransparentDrawingView->setWindowFlags(Qt::FramelessWindowHint | Qt::WindowStaysOnTopHint | Qt::Window | Qt::NoDropShadowWindowHint | Qt::X11BypassWindowManagerHint);

The expected result is that the mouse events can pass through the transparent background, like in Ubuntu, and Windows. 

Issue encountered on 10.14.6 (but same issue with Qt 5.9.5 and High Sierra)

 As you can see below, I can see QtCreator behind the transparent background, but I can't click though the background and interact with QtCreator. When I try to click on, the Mac menus and docks disappear and nothing happens, like if I had clicked on the background or in an object on the background.