title: MVVM Light Messenger executing multiple times
body: <p>I am using MVVM Light and am using Messages to communicate between ViewModels to let a ViewModel know when it is ok to execute something.  My problem is that I register for a message and then it receives it multiple times.  so to keep from my program executing something more than once I have to create boolean flags to see if it has already been recieved.  Any idea why it does this and how I can stop it?</p>