protected override async void OnNavigatedTo(NavigationEventArgs e)
        {
            await TitleBarHelper.SetVisibilityAsync(Visibility.Collapsed);

            TitleBarHelper.SetButtonBackgroundColor(Colors.Transparent);
            TitleBarHelper.SetButtonForegroundColor(ForegroundBrush.Color);

            Messenger.Default.Register <LoadContentMessage>(this, message =>
            {
                HtmlViewer.NavigateToString(ViewModel.FormattedHtml);
            });

            Messenger.Default.Register <TagsEditedMessage>(this, async message =>
            {
                if (message.Item.Id == ViewModel.Item.Model.Id)
                {
                    await HtmlViewer.InvokeScriptAsync("updateTagsElement", new List <string>()
                    {
                        ViewModel.BuildTagsHtml(message.Item)
                    });
                }
            });
        }
 protected override void OnNavigatedFrom(NavigationEventArgs e)
 {
     HtmlViewer.NavigateToString("<p></p>");
     Messenger.Default.Unregister(this);
 }