internal override void Attach(LegendTree legendTree)
        {
            if (legendTree == null)
            {
                return;
            }

            base.Attach(legendTree);

            LayerItemsOptions = legendTree.LayerItemsOptions;

            LayerItems.ForEach(item => item.Attach(legendTree));
            LegendItems.ForEach(item => item.Attach(legendTree));
        }
 internal override void Detach()
 {
     LayerItems.ForEach(item => item.Detach());
     LegendItems.ForEach(item => item.Detach());
     base.Detach();
 }