# ComboBox
self.name_store = Gtk.ListStore(int, str)
self.name_combo = Gtk.ComboBox.new_with_model_and_entry(self.name_store)
# insert roots
l_combo = self.take_roots()
for i in range(len(l_combo)):
    self.name_store.append([1, l_combo[i]])             # TODO: change 1 to new id
# TODO: do likewise
# data depends of chosen root
self.name_combo.connect("changed", self.take_data)
self.name_combo.set_entry_text_column(1)

def insert_root(self, button, data=None):
    ### insert & update text in controls

    tree_iter = self.name_combo.get_active_iter()
    try:
        entry = self.name_combo.get_child()
        cv_item = entry.get_text()      # text from ListStore - ComboBox
        idv_parent = 0
        idv_previous = 0
        # insert data
        Chain.create(id=next_id(Chain), c_item=cv_item, id_parent=idv_parent, id_previous=idv_previous, b_root=True)
        self.name_store.append([1, cv_item])
    except:
        pass