diff --git a/demos/gtk-demo/tree_store.c b/demos/gtk-demo/tree_store.c
index 6383ab7..944bc2c 100644
--- a/demos/gtk-demo/tree_store.c
+++ b/demos/gtk-demo/tree_store.c
@@ -32,7 +32,6 @@ struct _TreeItem
 {
   const char     *label;
   gboolean        AA;
-  gboolean        BB;
   gboolean        CC;
   TreeItem       *children;
 };
@@ -42,7 +41,6 @@ enum
 {
   COLUMN_0,
   COLUMN_1,
-  COLUMN_2,
 
   VISIBLE_COLUMN,
   WORLD_COLUMN,
@@ -52,33 +50,33 @@ enum
 /* tree data */
 static TreeItem item_name_0[] =
 {
-  { "A", TRUE, TRUE, TRUE, NULL },
-  { "B", FALSE, TRUE, FALSE, NULL },
-  { "C", FALSE, TRUE, FALSE, NULL },
+  { "A", TRUE, TRUE, NULL },
+  { "B", FALSE, TRUE, NULL },
+  { "C", FALSE, TRUE, NULL },
   { NULL }
 };
 
 static TreeItem item_name_1[] =
 {
-  { "A", FALSE, TRUE, FALSE, NULL },
-  { "B", FALSE, FALSE, FALSE, NULL },
-  { "C", FALSE, FALSE, TRUE, NULL },
-  { "D", FALSE, TRUE, TRUE, NULL },
+  { "A", FALSE, TRUE, NULL },
+  { "B", FALSE, FALSE, NULL },
+  { "C", FALSE, TRUE, NULL },
+  { "D", FALSE, TRUE, NULL },
   { NULL }
 };
 
 static TreeItem item_name_2[] =
 {
-  { "A", FALSE, FALSE, FALSE, NULL },
-  { "B", FALSE, FALSE, TRUE, NULL },
+  { "A", FALSE, FALSE, NULL },
+  { "B", FALSE, TRUE, NULL },
   { NULL }
 };
 
-static TreeItem toplevel[] =
+static TreeItem root[] =
 {
-  { "IT-0", FALSE, FALSE, FALSE, item_name_0 },
-  { "IT-1", FALSE, FALSE, FALSE, item_name_1 },
-  { "IT-2", FALSE, FALSE, FALSE, item_name_2 },
+  { "IT-0", FALSE, FALSE, item_name_0 },
+  { "IT-1", FALSE, FALSE, item_name_1 },
+  { "IT-2", FALSE, FALSE, item_name_2 },
   { NULL }
 };
 
@@ -88,7 +86,7 @@ create_model (void)
 {
   GtkTreeStore *model;
   GtkTreeIter iter;
-  TreeItem *item_0 = toplevel;
+  TreeItem *item_0 = root;
 
   /* create tree store */
   model = gtk_tree_store_new (NUM_COLUMNS,
@@ -107,7 +105,6 @@ create_model (void)
       gtk_tree_store_set (model, &iter,
                           COLUMN_0, item_0->label,
                           COLUMN_1, FALSE,
-                          COLUMN_2, FALSE,
                           VISIBLE_COLUMN, FALSE,
                           WORLD_COLUMN, FALSE,
                           -1);
@@ -121,7 +118,6 @@ create_model (void)
           gtk_tree_store_set (model, &child_iter,
                               COLUMN_0, item_1->label,
                               COLUMN_1, item_1->AA,
-                              COLUMN_2, item_1->BB,
                               VISIBLE_COLUMN, TRUE,
                               WORLD_COLUMN, item_1->CC,
                               -1);
@@ -135,7 +131,7 @@ create_model (void)
   return GTK_TREE_MODEL (model);
 }
 
-static void
+static void   //  https://www.gnu.org/software/guile-gnome/docs/gtk/html/GtkCellRendererToggle.html
 item_toggled (GtkCellRendererToggle *cell,
               char                  *path_str,
               gpointer               data)
@@ -186,7 +182,7 @@ add_columns (GtkTreeView *treeview)
   g_object_set (renderer, "xalign", 0.0, NULL);
   g_object_set_data (G_OBJECT (renderer), "column", (int *)COLUMN_1);
 
-  g_signal_connect (renderer, "toggled", G_CALLBACK (item_toggled), model);
+  //  g_signal_connect (renderer, "toggled", G_CALLBACK (item_toggled), model);
 
   col_offset = gtk_tree_view_insert_column_with_attributes (GTK_TREE_VIEW (treeview), -1, "Col 1", renderer, "active",
                                                             COLUMN_1, "visible", VISIBLE_COLUMN, "activatable", WORLD_COLUMN, NULL);
@@ -195,16 +191,6 @@ add_columns (GtkTreeView *treeview)
 //  gtk_tree_view_column_set_sizing (GTK_TREE_VIEW_COLUMN (column), GTK_TREE_VIEW_COLUMN_FIXED);
 //  gtk_tree_view_column_set_clickable (GTK_TREE_VIEW_COLUMN (column), TRUE);
 
-  /* BB column */
-  renderer = gtk_cell_renderer_toggle_new ();
-  g_object_set (renderer, "xalign", 0.0, NULL);
-  g_object_set_data (G_OBJECT (renderer), "column", (int *)COLUMN_2);
-
-  g_signal_connect (renderer, "toggled", G_CALLBACK (item_toggled), model);
-
-  col_offset = gtk_tree_view_insert_column_with_attributes (GTK_TREE_VIEW (treeview), -1, "Col 2", renderer, "active",
-                                                            COLUMN_2, "visible", VISIBLE_COLUMN, NULL);
-
 /*  column = */ gtk_tree_view_get_column (GTK_TREE_VIEW (treeview), col_offset - 1);
 //  gtk_tree_view_column_set_sizing (GTK_TREE_VIEW_COLUMN (column), GTK_TREE_VIEW_COLUMN_FIXED);
 //  gtk_tree_view_column_set_clickable (GTK_TREE_VIEW_COLUMN (column), TRUE);