QtQuick Window Dialog created dynamically can't be set with modality

When I create a qml component dynamically that has a Window as root that is flaged as Qt.Dialog (and only with a Dialog), it doesn't stop the input of the parent when I set the modality. Not with Application nor WindowModality
This happens when creating from javascript and also with a loader but not when it's directly inside the parent window.
Attached is a test app I used to reproduce, with combo boxes to select the possible combinations of windows and modality.