I have tried running the application in isolation and found that the error is now being rendered but the field is broken after I focus in and out of the field after the error.
I have deployed it in Google so you can try it: http://pacmapp.appspot.com
The HTML Panel seems to be causing this error. When I replaced it with a vertical panel, like in the example, it works fine.
Let me know if you can reproduce the issue or if you need more information.