public void set_tree_column_names (string[] namesArray)
        {

                int c=0;

                TreeViewColumn tvcol;

                tree.HeadersClickable = true;

                foreach (String colName in namesArray) {

                        tvcol = tree.AppendColumn (colName, new Gtk.CellRendererText (), "text", c++);
                        tvcol.SortIndicator = true;
                        tvcol.Clickable = true;
                        tvcol.SortColumnId = 0;

                }

        }