private void GetNodeTags( TreeNode parent, ManifestBuilder builder )
        {
            foreach ( TreeNode child in parent.Nodes )
             {
            GetNodeTags( child, builder );
             }

             if ( parent.Tag is RecipeSlotInfo )
             {
            RecipeSlotInfo info = parent.Tag as RecipeSlotInfo;
            builder.AddSlotInfo( info );
             }
        }