rem: GtkWidget *tree, *item;
add: GtkWidget *tree, *item, *sw;
context: GtkWidget * create_preferences_tree ( ){  GtkWidget *tree, *item;  GList *items = NULL;  GtkTreeIter iter;  GtkTreeViewColumn *column;  GtkCellRenderer *cell;  preference_tree_model = gtk_tree_store_new (2, 					      G_TYPE_STRING, 					      G_TYPE_POINTER);  tree = gtk_tree_view_new();  gtk_tree_view_set_model (GTK_TREE_VIEW (tree), GTK_TREE_MODEL (preference_tree_model));  selection = gtk_tree_view_get_selection (GTK_TREE_VIEW (tree));  cell = gtk_cell_renderer_text_new ();  column =     gtk_tree_view_column_new_with_attributes ("Categories",					      cell,					      "text", 0,					      NULL);  gtk_tree_view_append_column (GTK_TREE_VIEW (tree),			       GTK_TREE_VIEW_COLUMN (column));  g_signal_connect (selection, "changed", G_CALLBACK (selectionne_liste_preference), preference_tree_model);  return tree;}