diff --git a/(notes) b/(notes)
index cf7f1c1..3edc8aa 100644
--- a/(notes)
+++ b/(notes)
@@ -7,6 +7,7 @@ https://docs.gtk.org/gtk4/drag-and-drop.html           drag-and-drop
 https://docs.gtk.org/gtk4/class.GestureZoom.html       GtkGestureZoom  
 --------------------------------------------------------------------------------
 
+
 GTK_ORIENTATION_VERTICAL       GTK_ORIENTATION_HORIZONTAL
 
 g_signal_connect (button, "clicked", G_CALLBACK (printf("%s\n", text)), text);
diff --git a/contain.c b/contain.c
index 93dfac9..48d7111 100644
--- a/contain.c
+++ b/contain.c
@@ -92,6 +92,41 @@ GtkWidget *get_edit_space_page_new(){
 
 //------------------------------------------------------------------------------
 
+GtkWidget *get_selected_rules_vpaned_new(){
+  GtkPaned *V_selected_1_vs_2 = GTK_PANED (gtk_paned_new (GTK_ORIENTATION_VERTICAL));
+
+//  GtkWidget *règle_sélectionnée_n_1 = gtk_frame_new ("(1)");
+//  GtkWidget *règle_sélectionnée_n_2 = gtk_frame_new ("(2)");
+
+  GtkBox *up_box = GTK_BOX(gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 2));
+  gtk_box_append (up_box, GTK_WIDGET (get_image_GLUTAMATE()));
+  gtk_box_append (up_box, GTK_WIDGET(gtk_separator_new (GTK_ORIENTATION_VERTICAL)));
+  gtk_box_append (up_box, GTK_WIDGET (get_image_GLUTAMINE()));
+/*
+  GtkBox *bottom_box = GTK_BOX(gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 2));
+  gtk_box_append (bottom_box, GTK_WIDGET (get_image_PHENYLALANINE()));
+  gtk_box_append (bottom_box, GTK_WIDGET(gtk_separator_new (GTK_ORIENTATION_VERTICAL)));
+  gtk_box_append (bottom_box, GTK_WIDGET (get_image_DOPAMINE()));
+*/
+  GtkBox *bottom_box = GTK_BOX(gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 2));
+  gtk_box_append (bottom_box, GTK_WIDGET (get_image_ATP()));
+  gtk_box_append (bottom_box, GTK_WIDGET(gtk_separator_new (GTK_ORIENTATION_VERTICAL)));
+  gtk_box_append (bottom_box, GTK_WIDGET (get_image_AMP()));
+
+  gtk_paned_set_start_child (V_selected_1_vs_2, GTK_WIDGET (up_box));
+  gtk_paned_set_end_child (V_selected_1_vs_2, GTK_WIDGET (bottom_box));
+
+//  gtk_paned_set_start_child (V_selected_1_vs_2, GTK_WIDGET (règle_sélectionnée_n_1));
+//  gtk_paned_set_end_child (V_selected_1_vs_2, GTK_WIDGET (règle_sélectionnée_n_2));
+
+//  gtk_box_append ( GTK_BOX(règle_sélectionnée_n_1), GTK_WIDGET (up_box));//, GTK_WIDGET (get_image_GLUTAMATE()));
+//  gtk_box_append ( GTK_BOX(règle_sélectionnée_n_2), GTK_WIDGET (bottom_box));//, GTK_WIDGET (get_image_GLUTAMATE()));
+
+  return GTK_WIDGET (V_selected_1_vs_2);
+}
+
+
+
 GtkWidget *get_run_space_top_box(){
   GtkBox *top_box = GTK_BOX(gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 2));
   gtk_box_append (top_box, GTK_WIDGET (get_ELAPSED_TIME_ProgressBar()));
diff --git a/contain.o b/contain.o
index 52e970c..0c2d6cc 100644
Binary files a/contain.o and b/contain.o differ
diff --git a/display.c b/display.c
index 2804984..4139a91 100644
--- a/display.c
+++ b/display.c
@@ -224,3 +224,4 @@ GtkWidget *get_OBJECTS_and_SITUATIONS(){
   return objects_and_situations_horizontal_pane;
 }
 
+
diff --git a/hot.c b/hot.c
index 35b0d41..ad74525 100644
--- a/hot.c
+++ b/hot.c
@@ -15,44 +15,256 @@
 
 
 
-GtkWidget *get_selected_rules_vpaned_new(){
-  GtkPaned *V_selected_1_vs_2 = GTK_PANED (gtk_paned_new (GTK_ORIENTATION_VERTICAL));
+// Simplified TreeNode structure for demonstration purposes
+// --------------------------------------------------------
 
-//  GtkWidget *règle_sélectionnée_n_1 = gtk_frame_new ("(1)");
-//  GtkWidget *règle_sélectionnée_n_2 = gtk_frame_new ("(2)");
-
-  GtkBox *up_box = GTK_BOX(gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 2));
-  gtk_box_append (up_box, GTK_WIDGET (get_image_GLUTAMATE()));
-  gtk_box_append (up_box, GTK_WIDGET(gtk_separator_new (GTK_ORIENTATION_VERTICAL)));
-  gtk_box_append (up_box, GTK_WIDGET (get_image_GLUTAMINE()));
 /*
-  GtkBox *bottom_box = GTK_BOX(gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 2));
-  gtk_box_append (bottom_box, GTK_WIDGET (get_image_PHENYLALANINE()));
-  gtk_box_append (bottom_box, GTK_WIDGET(gtk_separator_new (GTK_ORIENTATION_VERTICAL)));
-  gtk_box_append (bottom_box, GTK_WIDGET (get_image_DOPAMINE()));
-*/
-  GtkBox *bottom_box = GTK_BOX(gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 2));
-  gtk_box_append (bottom_box, GTK_WIDGET (get_image_ATP()));
-  gtk_box_append (bottom_box, GTK_WIDGET(gtk_separator_new (GTK_ORIENTATION_VERTICAL)));
-  gtk_box_append (bottom_box, GTK_WIDGET (get_image_AMP()));
+ * Tree-related signals
+ */
 
-  gtk_paned_set_start_child (V_selected_1_vs_2, GTK_WIDGET (up_box));
-  gtk_paned_set_end_child (V_selected_1_vs_2, GTK_WIDGET (bottom_box));
+void on_tree_expander_toggled(GtkExpander *expander, gpointer user_data)
+{
+    // This is a conceptual callback for when an expander is toggled
+    GtkTreeListRow *row = GTK_TREE_LIST_ROW(user_data);
+    gboolean is_expanded = gtk_tree_list_row_get_expanded(row);
+    gtk_tree_list_row_set_expanded(row, !is_expanded);
+}
 
-//  gtk_paned_set_start_child (V_selected_1_vs_2, GTK_WIDGET (règle_sélectionnée_n_1));
-//  gtk_paned_set_end_child (V_selected_1_vs_2, GTK_WIDGET (règle_sélectionnée_n_2));
+void on_tree_setup_factory (GtkSignalListItemFactory *factory,
+                            GObject* object,
+                            gpointer user_data)
+{
+    GtkWidget* expander = gtk_expander_new (NULL);
+    gtk_list_item_set_child (GTK_LIST_ITEM(object), expander);
+    printf("[on_tree_setup_factory] here is an expander\n");
+}
 
-//  gtk_box_append ( GTK_BOX(règle_sélectionnée_n_1), GTK_WIDGET (up_box));//, GTK_WIDGET (get_image_GLUTAMATE()));
-//  gtk_box_append ( GTK_BOX(règle_sélectionnée_n_2), GTK_WIDGET (bottom_box));//, GTK_WIDGET (get_image_GLUTAMATE()));
+void on_tree_bind_factory (GtkSignalListItemFactory *factory,
+                           GObject* object,
+                           gpointer user_data)
+{
+    GObject *item;
+    const gchar *text;
+    GtkTreeListRow *row;
+    GtkListItem *list_item;
+    GtkWidget *expander;
 
-  return GTK_WIDGET (V_selected_1_vs_2);
+    list_item= GTK_LIST_ITEM(object);
+    row = gtk_list_item_get_item(list_item);
+    if (row != NULL) {
+        text = gtk_string_object_get_string(GTK_STRING_OBJECT(gtk_tree_list_row_get_item(row)));
+        expander = gtk_list_item_get_child(list_item);
+        gtk_expander_set_label(GTK_EXPANDER(expander), text);
+
+        // Disconnect previous signal handlers to avoid stacking them
+        g_signal_handlers_disconnect_by_func(expander, G_CALLBACK(on_tree_expander_toggled), row);
+
+        // Connect the signal handler
+        g_signal_connect(expander, "activate", G_CALLBACK(on_tree_expander_toggled), row);
+
+        gtk_widget_set_margin_start(expander, gtk_tree_list_row_get_depth(row)*20);
+        gboolean is_expanded = gtk_tree_list_row_get_expanded(row);
+        printf("[on_tree_bind_factory] here is %s content and expander is %d\n",
+               text,
+               is_expanded);
+    } else {
+        printf("[on_tree_bind_factory] here is NON content\n");
+    }
+}
+
+void on_tree_selection_changed (GtkSelectionModel* self, guint position,
+                           guint n_items, gpointer user_data)
+{
+    printf("[on_tree_selection_changed]\n");
+}
+
+struct TreeNode_t
+{
+    gchar *text;
+    struct TreeNode_t *child;
+    struct TreeNode_t *next;
+};
+
+// Function to create a new TreeNode instance
+static struct TreeNode_t *create_tree_node (const gchar* text)
+{
+    struct TreeNode_t *node = g_malloc0 (sizeof(struct TreeNode_t));
+    node->text = g_strdup(text);
+    node->child = NULL;
+    return node;
+}
+
+// Function to add a child node to a parent node
+static void add_child_node (struct TreeNode_t *parent, struct TreeNode_t *child)
+{
+    struct TreeNode_t *cur;
+
+    if (parent->child) {
+        cur = parent->child;
+        while (cur && cur->next) {
+            cur = cur->next;
+        }
+        cur->next = child;
+    } else {
+        parent->child = child;
+    }
+}
+
+// Recursive function to free a TreeNode and its children
+static void free_tree_node (struct TreeNode_t *node)
+{
+    struct TreeNode_t *cur;
+    struct TreeNode_t *tmp;
+
+    if (!node) return;
+
+    // free siblings
+    cur = node;
+    while (cur) {
+        tmp = cur->next;
+        g_free(cur);
+        cur = tmp;
+    }
+
+    // recursive free
+    free_tree_node(node->child);
+    g_free(node->text);
+    g_free(node);
+}
+
+// Function to simulate getting a GListModel of children for a given TreeNode
+GListModel* ui_tree_get_children_model (struct TreeNode_t *parent)
+{
+    struct TreeNode_t *child;
+
+    GtkStringList *list = NULL;
+
+    if (parent) {
+        printf("[ui_tree_get_children_model] here is %s content : ", parent->text);
+
+        child = parent->child;
+
+        if (child) {
+            list = gtk_string_list_new(NULL);
+        }
+        while(child) {
+             gtk_string_list_append(list, child->text);
+             printf("%s ", child->text);
+             child = child->next;
+        }
+    }
+    printf("\n");
+
+    return G_LIST_MODEL(list);
+}
+
+// GtkTreeListModelCreateModelFunc callback implementation
+GListModel* ui_tree_create_model_func(GObject *item, gpointer root)
+{
+    struct TreeNode_t *cur = (struct TreeNode_t *)root;
+    struct TreeNode_t *parent = NULL;
+
+    gchar *string =  gtk_string_object_get_string(GTK_STRING_OBJECT(item));
+
+    parent = root;
+    while (cur) {
+        if (strcmp(string, cur->text) == 0) {
+            break;
+        }
+
+        cur = cur->next;
+        if (cur == NULL) {
+            cur = parent->child;
+            parent = cur;
+        }
+    }
+
+    printf("[ui_tree_create_model_func] looked for %s in %s item\n",
+           cur->text,
+           string);
+
+    return ui_tree_get_children_model(cur);
+}
+
+// Application activation callback
+static void ui_create_tree (GtkWidget *target_widget)
+{
+    GtkStringList *model;
+    GtkTreeListModel *tree_model;
+    GtkSignalListItemFactory *factory;
+    GtkSingleSelection *selection_model;
+    GtkWidget *list_view;
+    GtkScrolledWindow *scrolled_window;
+
+    assert(target_widget);
+
+    // AD HOC XXX & no free()
+    struct TreeNode_t *tree_root = create_tree_node("Root");
+    struct TreeNode_t *ATP = create_tree_node("ATP");
+    struct TreeNode_t *ADP = create_tree_node("ADP");
+    struct TreeNode_t *AMP = create_tree_node("AMP");
+    struct TreeNode_t *adenine = create_tree_node("adénine");
+    struct TreeNode_t *ribose = create_tree_node("ribose");
+    struct TreeNode_t *PO4H3_1 = create_tree_node("phosphate 1");
+    struct TreeNode_t *PO4H3_2 = create_tree_node("phosphate 2");
+    struct TreeNode_t *PO4H3_3 = create_tree_node("phosphate 3");
+
+    add_child_node(tree_root, ATP);
+    add_child_node(tree_root, ADP);
+    add_child_node(tree_root, AMP);
+    add_child_node(ATP, adenine);
+    add_child_node(adenine, ribose);
+    add_child_node(ribose, PO4H3_1);
+    add_child_node(PO4H3_1, PO4H3_2);
+    add_child_node(PO4H3_3, PO4H3_3);
+
+    model = gtk_string_list_new(NULL);
+    gtk_string_list_append(model, tree_root->text);
+
+    // Create and setup the list view and item factory
+    factory = gtk_signal_list_item_factory_new ();
+    g_signal_connect (factory, "setup", G_CALLBACK(on_tree_setup_factory), NULL);
+    g_signal_connect (factory, "bind", G_CALLBACK(on_tree_bind_factory), NULL);
+
+    // Create a GtkTreeListModel
+    tree_model = gtk_tree_list_model_new(
+        G_LIST_MODEL(model),
+        FALSE, // Passthrough - False in actual usage with dynamic children retrieval
+        FALSE, // autoexpand
+        (GtkTreeListModelCreateModelFunc)ui_tree_create_model_func,
+        tree_root,
+        NULL //(GDestroyNotify)free_tree_node
+    );
+
+    selection_model = gtk_single_selection_new (
+                                            G_LIST_MODEL (tree_model));
+
+    gtk_single_selection_set_autoselect (selection_model, FALSE);
+    gtk_single_selection_set_can_unselect (selection_model, TRUE);
+    /* g_signal_connect (selection_model, "selection-changed", */
+    /*                                     G_CALLBACK(on_tree_selection_changed), NULL); */
+
+    list_view = gtk_list_view_new (selection_model, factory);
+
+    scrolled_window = gtk_scrolled_window_new();
+    gtk_scrolled_window_set_child(scrolled_window, list_view);
+
+    gtk_scrolled_window_set_policy (scrolled_window,
+                                    GTK_POLICY_AUTOMATIC,
+                                    GTK_POLICY_AUTOMATIC);
+    gtk_widget_set_vexpand(GTK_WIDGET(scrolled_window), TRUE);
+
+    gtk_box_append(GTK_BOX(target_widget), GTK_WIDGET(scrolled_window));
+    gtk_widget_show(GTK_WIDGET(scrolled_window));
+    gtk_widget_show(GTK_WIDGET(list_view));
 }
 
 GtkBox *get_rules_user_tree_new(){
   GtkBox *tree_sketch = GTK_BOX(gtk_box_new (GTK_ORIENTATION_VERTICAL, 2));
-  gtk_box_append (tree_sketch, GTK_WIDGET(gtk_separator_new (GTK_ORIENTATION_HORIZONTAL)));
-  gtk_box_append (tree_sketch, GTK_WIDGET (get_user_tree()));
-  gtk_box_append (tree_sketch, GTK_WIDGET(gtk_separator_new (GTK_ORIENTATION_HORIZONTAL)));
+//  gtk_box_append (tree_sketch, GTK_WIDGET(gtk_separator_new (GTK_ORIENTATION_HORIZONTAL)));
+//  gtk_box_append (tree_sketch, GTK_WIDGET (get_user_tree()));
+//  gtk_box_append (tree_sketch, GTK_WIDGET(gtk_separator_new (GTK_ORIENTATION_HORIZONTAL)));
+  ui_create_tree(tree_sketch);
   return tree_sketch;
 }
 
diff --git a/hot.o b/hot.o
index 8c00e0f..e7e80c4 100644
Binary files a/hot.o and b/hot.o differ
diff --git a/image/GTK4 tree.png b/image/GTK4 tree.png
new file mode 100644
index 0000000..64f912b
Binary files /dev/null and b/image/GTK4 tree.png differ
diff --git a/myprogram b/myprogram
index 64bb7b8..451bdc8 100755
Binary files a/myprogram and b/myprogram differ