The documentation of the clicked(MouseEvent mouse) states:

When handling this signal, changing the accepted property of the mouse parameter has no effect.

This is not correct, as when propagateComposedEvents attribute is set to true, changing the accepted property of the mouse parameter inside onClick: block indeed controls whether the actual event will be propagated to underlaying MouseArea or not.

The current texting is misleading in that it sugests, that you can not make event propagated once you started to handle it (enter onClick: block), what is not true (experimentally verified - see the demo project attached).