private void MeasureItem_Holding(object sender, HoldingRoutedEventArgs e)
{
var item = sender as FrameworkElement;
var measureItem = item.DataContext as MeasureItem;
if (Editor != null && measureItem != null && Editor.DeleteVertex.CanExecute(measureItem.CoordinateIndex))
FlyoutBase.ShowAttachedFlyout((FrameworkElement) sender);
}