OverlaySheet lacks background dimming for modal popups (QQC2.Overlay.modal)
OverlaySheet is not modal by default (for whatever reason which is strange on its own, because apparently the only user-facing difference is that non-modal dimmed popups let hover events pass, but both block clicks).
But if you override it to be modal, it looses that firm darkening backdrop dimming, because it doesn't have any QQC2.Overlay.modal
component set.
Seems like this is some of the KF6 porting artifact, since in KF5 times OverlaySheet had nothing to do with QQC2 popups and overlays.
@mart what do you think of this?