Callback SequenceFileLoad does not execute

[Exle]

My test sequence includes a callback named SequenceFileLoad. I have placed only the default "Message Popup" as a minimal test into the callback. But if I close and open the .seq-file nothing happens. The Message Popup is not being shown.

If I open a file of the examples (Overriding SequenceFilePostStepFailure Callback.seq) the PopUp in this .seq-File gets shown. What option am I missing?

[Exle]

I closed TestStand. I opened TestStand. Now it works.