Problem with gtk_tree_view_get_path_at_pos

[DaveMDS <list gurumeditation it>]

Hi all, I need to know wich row in a tree view is under the cursor while 
a drag operation occur,
These piece of code works great if the tree view as the header hide, if 
the header is visible
then gtk_tree_view_get_path_at_pos return a wrong value (because the 
header is counted as the firs row).
Is this a bug or I missed something?
Thanks
DaveMDS

gboolean on_drag_motion (GtkWidget *widget, GdkDragContext 
*drag_context, gint x, gint y, guint time, gpointer user_data){
   GtkTreeModel *model = gtk_tree_view_get_model(widget);
   GtkTreePath *path = NULL;
   GtkTreeIter iter;

   //Get path at pos
   gtk_tree_view_get_path_at_pos(GTK_TREE_VIEW(widget), x, y, &path, 
NULL, NULL, NULL);
       
   //Get iter at path
   gtk_tree_model_get_iter (model, &iter, path);
   
   //Get data
   gtk_tree_model_get( model, &iter, 6, &mafile,-1);
       
   gtk_tree_path_free(path);

   return TRUE;
}