private void UpdateOverlayImpl(OverlayViewModel overlay)
        {
            _overlay = overlay;

            OnPropertyChanged(() => HasOverlay);
            OnPropertyChanged(() => Overlay);
            OnPropertyChanged(() => OverlayHeader);
        }
        private void UpdateOverlay(OverlayViewModel overlay)
        {
            using (SuspendNotifications())
            {
                if (_overlay != null)
                {
                    ClearOverlay();
                }

                UpdateOverlayImpl(overlay);
            }
        }