Introduced with LabVIEW 2013, the Event Inspector added an ability to gain new understandings into the inner workings of our event structures
Event Inspector Windows
Use the Event Inspector Window to view the events in event queues at run time. This window also displays which VIs contain Event structures with registered events and which events those Event structures handled.
Select View»Event Inspector Window to display this window. You also can right-click an Event structure and select Event Inspector Window from the shortcut menu.
Read more: Event Inspector Window
Programmatically Inspect Event Queues
NI's Matt J came up with a way to even get to the event queues directly in LabVIEW - programmatically:
Read more: Programmatically Inspect Event Queues