diff --git a/src/main.c b/src/main.c
index d18e236..18d9b51 100644
--- a/src/main.c
+++ b/src/main.c
@@ -64,15 +64,11 @@ int main(int argc, char **argv)
     app = gem_graph_client_application_new("org.alec.gemgraph",
                                            G_APPLICATION_DEFAULT_FLAGS);
 
-    g_signal_connect (app, "activate", G_CALLBACK (on_activate_window_creation), // in : "sand_box_2.c :"
-                      "This signal comes from main.c and is displayed by the sand_box window\n");
-
+    g_signal_connect (app, "activate", G_CALLBACK (on_activate_window_creation),
+                      "This signal comes from main.c");
 
     //  Jean 2024-01-20  Je désactive la visualisation de la fenêtre principale
-    //                   pour travailler dans une fenêtre minimale (cf. sand_box)
-    //
-    //  gtk_window_present(window);  <   cf.  application.c   ligne 122
-
+    //                   pour ne travailler que dans la fenêtre de sand_box.c
 
     res = g_application_run(G_APPLICATION(app), argc, argv);
     return res;
diff --git a/src/ui/sand_box.c b/src/ui/sand_box.c
index 2c55751..6c8ee14 100644
--- a/src/ui/sand_box.c
+++ b/src/ui/sand_box.c
@@ -25,33 +25,12 @@
 #include <gtk-4.0/gtk/gtk.h>
 #include <gdk/gdk.h>
 #include <glib-2.0/glib.h>
-
 #include "../../include/base.h"
 #include "../../include/ui.h"
 
-static enum { NAME_COLUMN };
-
-   /* custom function to fill the model with data */
-static GtkWidget populate_tree_model (my_store){
-    GtkWidget *my_tree;
-    GtkTreeViewColumn *my_column;
-    GtkCellRenderer *my_renderer;
-
-    GtkTreeIter my_iter_1, my_iter_2;
-    gtk_tree_store_append (my_store, &my_iter_1, NULL);  // Acquire an iterator
-    gtk_tree_store_set (my_store, &my_iter_1, NAME_COLUMN, "value A", -1);
-    gtk_tree_store_append (my_store, &my_iter_2, &my_iter_1);  // Acquire a child iterator
-    gtk_tree_store_set (my_store, &my_iter_2, NAME_COLUMN, "value B", -1);
-    my_column = gtk_tree_view_column_new_with_attributes ("names", my_renderer, "text", NAME_COLUMN, NULL);
-    gtk_tree_view_append_column (GTK_TREE_VIEW (my_tree), my_column);
-
-    return *my_tree;
-};
-
-
-
-static void on_button_action (GtkWidget *widget, gpointer data) {if (data) g_print (data);}
-static void on_destroy (GtkWidget *widget, gpointer data) { if (data) g_print (data);  exit(0);}
+int n = 0;
+static void on_button_action (GtkWidget *widget, gpointer data){n++; g_print (data, n);}
+static void on_destroy (GtkWidget *widget, gpointer data) {if (data) g_print (data);  exit(0);}
 
 void on_activate_window_creation (GtkApplication *app, gpointer data) {
     GtkWidget *my_window;
@@ -69,21 +48,22 @@ void on_activate_window_creation (GtkApplication *app, gpointer data) {
     gtk_widget_show (my_window);  //    show != present
 
     my_button = gtk_button_new_with_label (my_button_title);
-    g_signal_connect(G_OBJECT (my_button), "clicked", G_CALLBACK(on_button_action), "button clicked  (could use some data)\n");
-//  g_signal_connect_swapped  (my_button,  "clicked", G_CALLBACK (gtk_window_close), my_window);
+    g_signal_connect(G_OBJECT (my_button), "clicked", G_CALLBACK(on_button_action), "button clicked  (n = %d)\n");
+//  g_signal_connect_swapped  (my_button,  "clicked", G_CALLBACK (gtk_window_close), my_window);  //  <  Then my_button closes my_window
     g_signal_connect(G_OBJECT (my_window), "destroy", G_CALLBACK(on_destroy), "closes window using exit(0)\n");
 
-    gtk_box_append(GTK_BOX (my_box), GTK_WIDGET(my_button)); //  gtk_window_set_child (GTK_WINDOW (my_window), my_button);
+    gtk_box_append(GTK_BOX (my_box), GTK_WIDGET(my_button)); //  else : gtk_window_set_child (GTK_WINDOW (my_window), my_button);
 
-    if (data) g_print (data);
+    if (data) {g_print (data);  g_print (" and is displayed by [on_activate_window_creation()] in the sand_box window.\n");}
     printf("-------------------------------------------------------------------------------------------------------------------------------------------\n\
 [sand_box.c  >  on_activate_window_creation()]  >  widgets examples are in user/jean/01/GTK4/tree (learning)/The_Gnome_way/demos/gtk-demo <\n");
 }
 
 //------------------------------------------------------------------------------
 
-//  guix shell -m manifest.scm       make clean && clear && time make run
-//  GOBJECT_DEBUG=instance_count     GIO  Gnome Input Output
+//  guix shell -m manifest.scm && pkg-config --libs gtk4
+//  make clean && clear && time make run
+//  GOBJECT_DEBUG=instance_count     GIO = Gnome Input Output
 
 // https://docs.gtk.org/
 // https://docs.gtk.org/gtk4/
@@ -109,3 +89,4 @@ void on_activate_window_creation (GtkApplication *app, gpointer data) {
 //
 //
 
+