diff --git a/gtk_treeview_example b/gtk_treeview_example
index aeaf159..4163322 100755
Binary files a/gtk_treeview_example and b/gtk_treeview_example differ
diff --git a/main.c b/main.c
index 639cbe6..2ae58cc 100644
--- a/main.c
+++ b/main.c
@@ -48,6 +48,17 @@ void add_child_node (struct TreeNode_t *parent, struct TreeNode_t *child)
     }
 }
 
+static insert_data()    //  (TreeNode_t *root)
+{
+    struct TreeNode_t *A = create_tree_node("A");    add_child_node(root, A);
+    struct TreeNode_t *B = create_tree_node("B");    add_child_node(A, B);
+    struct TreeNode_t *C = create_tree_node("C");    add_child_node(B, C);
+    struct TreeNode_t *D = create_tree_node("D");    add_child_node(C, D);
+    struct TreeNode_t *E = create_tree_node("E");    add_child_node(D, E);
+    struct TreeNode_t *F = create_tree_node("F");    add_child_node(E, E);
+    struct TreeNode_t *G = create_tree_node("G");    add_child_node(E, A);
+}
+
 // Recursive function to free a TreeNode and its children
 void free_tree_node (struct TreeNode_t *node)
 {
@@ -215,20 +226,7 @@ int main (int argc, char **argv)
 {
     // Create a simple tree structure
     root = create_tree_node("Root");
-    struct TreeNode_t *A = create_tree_node("A");
-    struct TreeNode_t *B = create_tree_node("B");
-    struct TreeNode_t *C = create_tree_node("C");
-    struct TreeNode_t *D = create_tree_node("D");
-    struct TreeNode_t *E = create_tree_node("E");
-    struct TreeNode_t *F = create_tree_node("F");
-    struct TreeNode_t *G = create_tree_node("G");
-    add_child_node(root, A);
-    add_child_node(A, B);
-    add_child_node(B, C);
-    add_child_node(C, D);
-    add_child_node(D, E);
-    add_child_node(E, E);
-    add_child_node(E, A);
+    insert_data();
 
     GtkApplication *app = gtk_application_new("org.gtk.example", G_APPLICATION_FLAGS_NONE);
     g_signal_connect(app, "activate", G_CALLBACK(app_activate), NULL);
@@ -238,3 +236,7 @@ int main (int argc, char **argv)
     return status;
 }
 
+
+//----------------------------------------------------------------------------------------
+// guix shell -m manifest.scm && pkg-config --libs gtk4
+// make clean && clear && make && ./gtk_treeview_example