IMonitor / No response

I'm using Tapestry 2.3. I subclassed Engine, overrode the getMonitor method
to return a class that simply prints out the method being called. It never
seems to be called. Do I have to "turn something on"?

The engine class is set correctly in the .application file. The method is as
below:
    public IMonitor getMonitor(RequestContext context)
    {
        return new Monitor( context );
    }    


Joel