TreeNode curNode = this.trvFolder.GetNodeAt(e.X, e.Y)

private void trvFolder_NodeMouseClick(object sender, TreeNodeMouseClickEventArgs e)
        {
            if (e.Button == MouseButtons.Right)
            {
                Point pos = new Point(e.Node.Bounds.X + e.Node.Bounds.Width, e.Node.Bounds.Y + e.Node.Bounds.Height / 2);
                this.cmsFolderMenu.Show(this.trvFolder, pos);
            }
}