ApplicationWindow.onClosing can't know intent to quit

I have a QML app that handles ApplicationWindow.closing signal. I use an onClosing handler to avoid quitting and hide the app window instead. I also setup a MenuBar with a Quit action that actually quits.

When I use the macOS dock menu to quit the application, it just calls ApplicationWindow.closing which hides the window and doesn't quit. There is no way to know the intent behind the closing of the window.

Probably a way to know that the system wants to kill the app is needed. Or Qt should at least trigger the custom Quit action, if present. I feel this issue is caused by the fact that Qt mixes the concept of window closing with the concept of application quitting.