Events are not implemented very well right now. If you do not have many manualy added transactions, this is the best way because you cannot automaticaly undo the changes caused by the Event. However, you can change the transactions back by hand and just ignore the wrong entries in the Events field - they do not actualy do anything after the initial creation of the event. Delete your historic quotes aswell and download them again to get back to square one.
A “cleaner” workaround can be done in the XML file: BACK UP THE XML. Find the security and split event and delete the entries. This will clean your event tab. BUT this will still not change the transactions and quotes back, so you will have to do that by hand in PP anyway.
So yes: Deleting the security and doing it again will most likely be your best way. Remember to create a backup before using the Split Event again.
@AndreasB @Ragas Wie wäre es mit einem automatischen Backup und einem entsprechenden Hinweis, bevor PP ein Event erzeugt? Wir haben immer wieder Leute, die sich mit der Funktion ihre Buchungen zerschießen.