I see. I have tried setting the global variable to nothing and then
setting it back to Application, the events still don't fire.

In fact, even if i unload and reload the add-in that traps these events,
it still can't trap them.

Tom Ogilvy wrote:

When you instantiate application level events, you create a global variable.
When an error occurs while debugging I assume you hit the reset button which
clears that variable.