error designer "the following errors must be resolved" with msmq
===

I'm working in VS 2012 RC.
I have a class which inherits from MessageQueue (add reference to System.Messaging.dll ), when I want to open it in the solution explorer I see the following error:

"To prevent possible data loss before loading the designer, the following errors must be resolved:   "
"Format name is invalid. "

When I deleted  " : MessageQueue "  the problem is fixed.

my code: 

    public class QueueMSMQ : MessageQueue
    {
      //my own class
    }


thanks!