diff --git a/src/ui/tree.c b/src/ui/tree.c
index 5dae879..f8265ae 100644
--- a/src/ui/tree.c
+++ b/src/ui/tree.c
@@ -28,10 +28,18 @@
 #include "../../include/base.h"
 #include "../../include/ui.h"
 
+GtkListStore *list_store;
+
+
 void tree_c_printing_test(void)
 {
+    list_store = gtk_list_store_new (2, G_TYPE_STRING, G_TYPE_UINT);
+
     printf("tree_c_printing_test() \
-------------------------------------------------------\n\
-trying : https://en.wikibooks.org/wiki/GTK\%\2B_By_Example/Tree_View/Tree_Models\n");
+------------------------------------------------------\n\n\
+trying : https://en.wikibooks.org/wiki/GTK\%\2B_By_Example/Tree_View/Tree_Models\n\n\
+cf. tuto : This 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");
 }