fix the rendering of traces that generate event/states in a hierarchy

src/trace/DrawTrace.hpp

@@ -389,7 +389,8 @@ public:
             c++) {
             if(is_in_set(*c,set_container)){
                 container = *c;
-                position = (int)_container_positions[container];
+
+                position = (int)_container_positions[container] + _container_sizes[container] - 1;
 
                 state_tree = container->get_states();
                 event_tree = container->get_events();