draw first meeting

StackPanel.cpp

@@ -41,7 +41,7 @@ PositionalProperties StackPanel::draw(const PositionalProperties & positionals)
   };
 
   for(auto i = 0; i < itmes.size; i++) {    
-    auto callback = itmes.callbacks[i];
+    auto & callback = itmes.callbacks[i];
     auto last = callback(inner);
     inner = move(inner, last);
   }