private void Node_OnNodeRemoved(ISQNode node)
        {
            node.OnNodeRemoved -= Node_OnNodeRemoved;
            HierarchyNode hnode = node as HierarchyNode;

            CleanHierarchyNode(hnode);
        }
        private void Node_OnFileRemoved(ISQNode node)
        {
            SQProjectFileNode fnode = node as SQProjectFileNode;

            node.OnNodeRemoved -= Node_OnFileRemoved;
            RemoveNodesWithFilepath(fnode.Url);
            int d;

            while ((d = _instance.IndexOf(fnode.Url)) != -1)
            {
                if (d != -1)
                {
                    _instance.Children.RemoveAt(d);
                }
            }
            _nodes.Remove(fnode);
        }