public void Add()
        {
            Debug.Assert(documentNode.TreeNode.Parent == null);
            if (documentNode.TreeNode.Parent != null)
            {
                throw new InvalidOperationException();
            }
            Debug.Assert(!restoreIndex || origIndex >= 0);

            documentTreeView.AddNode(documentNode, origIndex);

            bool b = documentNode.Document.ModuleDef == null ||
                     (documentTreeView.FindNode(
                          documentNode.Document.AssemblyDef != null ?
                          (object)documentNode.Document.AssemblyDef :
                          documentNode.Document.ModuleDef) == documentNode);

            Debug.Assert(b);
            if (!b)
            {
                throw new InvalidOperationException();
            }
        }