This help page is for version 3.4. The latest available help is for version 5.1.
This action can be used when you want a message box to pop-up on the machine that is running the monitoring service with details about a recent anomaly. The Message Box Action keeps track of how many more message boxes are waiting to be shown, and lets you cancel them all at once if you choose to.
As you can see below, no configuration is necessary for this action.
Note: Message Boxes shown by services are not visible in Terminal Services sessions--they can only be seen on the primary console. This is a feature/limitation of the Windows operating system.