private void menuItem16_Click(object sender, EventArgs e)
{
var selected = projtree.SelectedNode as ExTreeNode;
if (selected == null) return;
var path = selected.Name;
var fileName = Path.ChangeExtension(path, "") + "-Copy" + Path.GetExtension(path);
File.Copy(path, fileName);
var parent = selected.Parent as ExTreeNode;
if (parent != null && parent.Type == ProjectNodeType.Folder)
parent.Nodes.Add(new ExTreeNode(Path.GetFileName(fileName), fileName, ProjectNodeType.File));
}