diff --git a/demos/gtk-demo/tree_store.c b/demos/gtk-demo/tree_store.c
index 8d33e31..1d599a1 100644
--- a/demos/gtk-demo/tree_store.c
+++ b/demos/gtk-demo/tree_store.c
@@ -70,55 +70,52 @@ static TreeItem R[] = {{ "A", A }, { "B", B }, { NULL }};
 static TreeItem O[] = {{ "R", R }, { NULL }}; //  Artefact added for symetry
 
 //  iterate_node(model, item_0, item_1, &iter, &child_iter);
-static GtkTreeModel *
-iterate_node(GtkTreeStore *model,
-             TreeItem    *item_parent,  TreeItem    *item_children,
-             GtkTreeIter iter_parent,  GtkTreeIter iter_children)
-{  printf("parent, children : %s -> %s    %p -> %p    %p -> %p    %p -> %p    %p -> %p\n",\
-         item_parent->label, item_children->label,\
-         item_parent, item_children,
-         &item_parent, &item_children,
-         iter_parent, iter_children,
-         &iter_parent, &iter_children);
-  /* gtk_tree_store_append (model, &iter_children, &iter_parent); */
-  /* gtk_tree_store_set (model, &iter_children, COLUMN_0, item_children->label, -1); */
-  return GTK_TREE_MODEL (model);
+static void iterate_node(GtkTreeStore *model,
+             GtkTreeIter *iter_children,
+             TreeItem *item_children,
+             GtkTreeIter *iter_parent)
+{
+  gtk_tree_store_append (model, iter_children, iter_parent);
+  gtk_tree_store_set (model, iter_children, COLUMN_0, item_children->label, -1);
 }
 
 static GtkTreeModel *
 create_model (void)
 {
+  TreeItem *item_0, *item_1, *item_2;
+  GtkTreeIter iter_0, iter_1, iter_2;
+
   GtkTreeStore *model = gtk_tree_store_new (NUM_COLUMNS, G_TYPE_STRING);
 
-  TreeItem *item_0 = O->children;
-  while (item_0->label) {
-      GtkTreeIter iter;
-   //   iterate_node(model, O, item_0, (GtkTreeIter) model, iter);
-      gtk_tree_store_append (model, &iter, NULL);
-      gtk_tree_store_set (model, &iter, COLUMN_0, item_0->label, -1);
+  if (O->children) {
+    item_0 = O->children;
 
-      TreeItem *item_1 = item_0->children;
-      while (item_1->label) {
-          GtkTreeIter child_iter;
-          iterate_node(model, item_0, item_1, iter, child_iter);
-          gtk_tree_store_append (model, &child_iter, &iter);
-          gtk_tree_store_set (model, &child_iter, COLUMN_0, item_1->label, -1);
+    while (item_0->label) {
+      printf("item_0 = %s\n", item_0->label);
+      iterate_node(model, &iter_0, item_0, NULL);
 
-          TreeItem *item_2 = item_1->children;
-          while (item_2->label) {
-              GtkTreeIter child_child_iter;
-              iterate_node(model, item_1, item_2, child_iter, child_child_iter);
-              gtk_tree_store_append (model, &child_child_iter, &child_iter);
-              gtk_tree_store_set (model, &child_child_iter, COLUMN_0, item_2->label, -1);
+      if (item_0->children) {
+        item_1 = item_0->children;
 
+        while (item_1->label) {
+          printf("[case item1 %s]\n",item_1->label);
+          iterate_node(model, &iter_1, item_1, &iter_0);
+
+          if (item_1->children) {
+            item_2 = item_1->children;
+
+            while (item_2->label) {
+              printf("[case item2 %s]\n",item_2->label);
+              iterate_node(model, &iter_2, item_2, &iter_1);
               item_2++;
+            }
           }
-
           item_1++;
         }
-
+      }
       item_0++;
     }
+  }
 
   return GTK_TREE_MODEL (model);
 }