diff --git a/src/ui/tree.c b/src/ui/tree.c
index dbc37de..9689778 100644
--- a/src/ui/tree.c
+++ b/src/ui/tree.c
@@ -52,15 +52,18 @@ static TreeItem A[] = {{"D", D}, {NULL}}, B[] = {{"E", E}, {NULL}};
 static TreeItem R[] = {{"A", A}, {"B", B}, {"C", C}, {NULL}};
 static TreeItem O[] = {{"ROOT", R}, {NULL}}; //  Artefact added for symmetry
 
+static GtkWidget *my_tree_view; //   = NULL;
+static GListStore *my_list_model = NULL;
+
 static void
 add_item (GtkWidget *button, gpointer data)
 {
   TreeItem foo;
-  GtkTreeIter current, iter;
+  GtkTreeView *treeview = my_tree_view; //  (GtkTreeView *)data;
+  GtkTreeModel *model = my_list_model;  //  gtk_tree_view_get_model (treeview);
   GtkTreePath *path;
-  GtkTreeModel *model;
   GtkTreeViewColumn *column;
-  GtkTreeView *treeview = NULL; //  (GtkTreeView *)data;
+  GtkTreeIter current, iter;
 }
 
 static void
@@ -68,10 +71,10 @@ remove_item (GtkWidget *widget, gpointer data)
 {
   printf("From 'tree.c' (line 130),  remove item()  >   no item selected (or can't get it ?)\n");
 
+  GtkTreeView *treeview = my_tree_view; //  (GtkTreeView *)data;
+  GtkTreeModel *model = my_list_model;  //  gtk_tree_view_get_model (treeview);
+  GtkTreeSelection *selection = gtk_tree_view_get_selection (treeview);
   GtkTreeIter iter;
-  GtkTreeView *treeview = NULL; //  (GtkTreeView *)data;
-  GtkTreeModel *model = NULL; //  gtk_tree_view_get_model (treeview);
-  GtkTreeSelection *selection = NULL; //  gtk_tree_view_get_selection (treeview);
 }
 
 static void
@@ -80,7 +83,7 @@ cell_edited (GtkCellRendererText *cell,
              const char          *new_text,
              gpointer             data)
 {
-  GtkTreeModel *model = (GtkTreeModel *)data;
+  GtkTreeModel *model = my_list_model;  //  gtk_tree_view_get_model (treeview);
   GtkTreePath *path = gtk_tree_path_new_from_string (path_string);
   GtkTreeIter iter;
 }
@@ -118,13 +121,12 @@ static GListStore *create_node_recursive (GListStore *model,
 
 GtkWidget *create_my_tree_model(GtkBox *runlib_objects)
 {
-    GListStore *my_list_model = NULL;
     GtkWidget *my_scrolled_window = NULL;
-    GtkWidget *my_tree_view = NULL;
     GtkCellRenderer *my_renderer = NULL;
 
     my_list_model = create_node_recursive (my_list_model, O, NULL, 0);
     my_tree_view = gtk_tree_view_new_with_model (my_list_model);
+
     gtk_tree_view_set_headers_visible (GTK_TREE_VIEW (my_tree_view), FALSE);
     gtk_tree_view_set_enable_tree_lines (GTK_TREE_VIEW (my_tree_view), TRUE);
     gtk_widget_set_vexpand (my_tree_view, TRUE);
@@ -161,7 +163,7 @@ print_hello (GtkWidget *widget,
 {
     static int nb;
     nb++;
-    printf("From 'tree.c',  >  button clicked  (n = %d)\n", nb);
+    printf("From 'tree.c',  >  %s added and button clicked  (n = %d)\n", data, nb);
 }
 
 GtkWidget *create_my_button_test(GtkBox *runlib_objects)
@@ -173,7 +175,7 @@ GtkWidget *create_my_button_test(GtkBox *runlib_objects)
     gtk_box_append(runlib_objects, button);
     gtk_widget_show(button);
 
-    g_signal_connect (button, "clicked", G_CALLBACK (print_hello), NULL);
+    g_signal_connect (button, "clicked", G_CALLBACK (print_hello), "some data");
 
     return button;
 }