Using Trees

[Joe LaBarbera <jlabarbera11 gmail com>]

Hi,

I was trying to append allow a user to click a button that would allow 
an additional column to be appended to my tree.

This is what I have:

void treetstruct::add_column()
{
    Gtk::TreeModelColumn<unsigned> newcol = columns.addcol();

    treeview.append_column_editable("New", columns.cols.back());
}

        Gtk::TreeModelColumn<unsigned> addcol()
        {
               Gtk::TreeModelColumn<unsigned> newcol;
               cols.push_back(newcol);
               add(cols.back());

               return cols.back();
        }

The column will appear; however, when I attempt to change values, they 
are automatically erased, and there are many errors that appear in the 
command line.  If anyone could help, even by providing additional 
information on trees in general, I would really appreciate it.