[gtkmm] TreeView.set_cursor weirdness

[Steve Przepiora <steve przepiora org>]

Hello I am having a problem with set_cursor, according to the
documentation calling set_cursor will select the row and start editing
the column. the following is the section of code I am using:

// create the new row
	Gtk::TreeRow row = *(model->append());
	row[columns.url] = "Add the new URL here.";
	row[columns.editable] = true;

//start editing the new row
	char buff[13];
	snprintf(buff,13,"%d",model->children().size());
	Glib::ustring p(buff);
	const Gtk::TreeModel::Path path(p);
	//list.scroll_to_cell(path,*urlcolumn,false,0,0);
	list.set_cursor(path,*urlcolumn,true);

urlcolumn is the one and only column that is showing in the treeview.

The only thing I can think of is I am creating the Path incorrectly, is
there an better way to create the Path?

Steve