I wrote: "Are you using the Submit button and/or a shortcut key for the TEB? And I suppose it is not validated. Then the event can be the On Success for the TEB".
A TEB is an interactive object. If it is not validated, in the Action accordion you can only use the On Success action to trigger that conditional advanced action. Have a look at this blog post about all the possible events to trigger actions:
http://blog.lilybiri.com/events-and-advanced-actions
Lilybiri