Where Else Could the Problem Be Coming From?

Spend some time thinking about where the source of the problem might be. If you don't know which ER event is causing an error, try to isolate it. For example, you might be able to temporarily disable the ER one event at a time to see if the error still happens. You can try to repeat the processing of a single event by doing unnatural actions in the GUI, like toggling up and down between grid rows to force the execution of the Row Is Exited event. There are no predefined debugging strategies that will work in any given situation. Be creative and be persistent, until you narrow down the problem to its source.