public void TraverseUpwards(DesignerItemBase item)
        {
            if (!ExecutionPlan.Contains(item))
            {
                ExecutionPlan.Add(item);
            }

            var predessorItems = flowGraph.GetPredecessorNodes(item);

            foreach (var predessorItem in predessorItems)
            {
                TraverseUpwards(predessorItem);
            }
        }