diff --git a/include/ui.h b/include/ui.h
index d595d32..283da49 100644
--- a/include/ui.h
+++ b/include/ui.h
@@ -118,7 +118,13 @@ void ui_send_internal_notification  (const char *message);
 void ui_close_internal_notification (void);
 void ui_toggle_sidebar              ();
 
+/* -------------------------------------------------------------------------- */
+
+// Tree primitives
+
+void traverse_list_store (GtkListStore *liststore);
 void onTreeViewRowActivated (GtkTreeView *view, GtkTreePath *path,
                              GtkTreeViewColumn *col, gpointer userdata);
+
 void tree_c_printing_test(void);
 
diff --git a/src/ui/tree.c b/src/ui/tree.c
index 20f174b..4d8f243 100644
--- a/src/ui/tree.c
+++ b/src/ui/tree.c
@@ -29,7 +29,35 @@
 #include "../../include/ui.h"
 
 GtkListStore *list_store;
+GtkTreeIter   iter;
 
+  /***********************************************************
+  *                                                          *
+  *  Going through every row in a list store                 *
+  *                                                          *
+  ***********************************************************/
+
+  void
+  traverse_list_store (GtkListStore *liststore)
+  {
+    GtkTreeIter  iter;
+    gboolean     valid;
+
+    g_return_if_fail ( liststore != NULL );
+
+    /* Get first row in list store */
+    valid = gtk_tree_model_get_iter_first(GTK_TREE_MODEL(liststore), &iter);
+
+    while (valid)
+    {
+       /* ... do something with that row using the iter ...          */
+       /* (Here column 0 of the list store is of type G_TYPE_STRING) */
+       gtk_list_store_set(liststore, &iter, 0, "Joe", -1);
+
+       /* Make iter point to the next row in the list store */
+       valid = gtk_tree_model_iter_next(GTK_TREE_MODEL(liststore), &iter);
+    }
+  }
  /*************************************************************
  *                                                            *
  *   Converting a GtkTreePath into a GtkTreeIter              *
@@ -68,11 +96,17 @@ tree_c_printing_test(void)
 {
     list_store = gtk_list_store_new (2, G_TYPE_STRING, G_TYPE_UINT);
 
+    /* Append empty rows to the list store. Iter will point to the new row */
+    gtk_list_store_append(list_store, &iter);
+    gtk_list_store_append(list_store, &iter);
+    gtk_list_store_append(list_store, &iter);
+
     printf("tree_c_printing_test() \
 ---------------------------------------------------------\n\n\
 (https://en.wikibooks.org/wiki/GTK (modulo) 2B_By_Example/Tree_View/Tree_Models)\n\n\
-cf. tuto : This creates a new list store with two columns.\n\
+cf. tuto : gtk_list_store_new (2, G_TYPE_STRING, G_TYPE_UINT)  - (cf. line 69)\n\
+           creates a new list store with two columns.\n\
 Column 0 stores a string and column 1 stores an unsigned integer for each row.\n\
-At this point the model has no rows yet of course.\n");
+Three empty lines have been added to the model - (cf. line 100).\n");
 }