Is there any simple way how to make a Gtk.Treeview updating its columns on edit? 

I build the Treeview based on a Gtk.ListStore model. I initialize the cells like this:

```
Gtk.CellRendererText valueCells = new Gtk.CellRendererText ();
valueCells.editable = true;
tree_view.insert_column_with_attributes (-1, "Key", valueCells, "text", 0);
tree_view.insert_column_with_attributes (-1, "Value", valueCells, "text", 1);

```

I'm now able to select and edit the columns until I exit the Selection. Neither the TreeView nor the ListStore is updated. Tried several solutions I found written in different languages but nothing worked. I understood i have to update the model, but couldn't figure out how to find the reference to that.. Do I miss something essential? O.o