I found the problem trying to show radmessagebox while executing a second thread process. As you probably know better than me, this is not a good practise due to problems in programm flow. Now when I´m passing all my outputs to the main thread, all messages are centered again and they work great.
I´m developing a custom user control, which in a certain operation is launching a second thread and executing a couple of sentences in another class. If you include on that code (the second thread code being executed from another class) any radMessageBox, these will not appear in the center.
Thanks and regards,