public bool ShowOptions(OptionsCollectionViewModel viewModel)
{
var window = new OptionsWindow();
window.DataContext = viewModel;
window.Icon = BitmapFrame.Create(new Uri("pack://application:,,,/CalDavSynchronizer;component/Resources/ApplicationIcon.ico"));
ElementHost.EnableModelessKeyboardInterop(window);
viewModel.RequestBringIntoView += delegate { window.BringIntoView(); };
return(window.ShowDialog().GetValueOrDefault(false));
}