private async void ContentListView_ItemClick(object sender, ItemClickEventArgs e)
        {
            if (IsIndexPanelOpen)
            {
                IsIndexPanelOpen = false;
                return;
            }

            var line = (LineViewModel)e.ClickedItem;

            if (!line.IsImage && !ViewModel.EnableComments)
            {
                return;
            }

            var container = ContentListView.ContainerFromItem(line);

            ((FrameworkElement)CommentsFlyout.Content).DataContext = line;
            CommentsFlyout.ShowAt((FrameworkElement)container);
            //CommentInputBox.Focus(Windows.UI.Xaml.FocusState.Unfocused);
            if (line.HasComments && !line.IsLoading)
            {
                await line.LoadCommentsAsync();
            }
        }