Hello again, Now the problem is when I create a class that use Traits, SystemChangeNotifier sends two messages to report this creation: 1st for class added without traits, and 2nd for class modified to use this trait. And this last message has Object as old class instead of ClassForTesting without traits. For example: Object subclass: #ClassForTesting uses: TSortable instanceVariableNames: 'a' classVariableNames: '' poolDictionaries: '' category: 'OOSCM-ClientImageTest' Can I change those messages to use only one message that includes traits? Is not this better? What do you suggest? ----- eze -- View this message in context: http://forum.world.st/SystemChangeNotifier-and-Traits-tp4073962p4073962.html Sent from the Pharo Smalltalk mailing list archive at Nabble.com.