Hello,
This is no problem, it makes things a lot easier for you. As you can retrieve the EventDefinition directly like this:
EventDefinition ed = BusinessKeyLookup.getEventDefinitionByBusinessKey(jcsSession, Event_Name);
This way no truncation is required and also you get around the (potential) problem with events in different Partitions.
Also, the dropdown will filter, although it is case sensitive, if you type TEST you only get TEST and not Test.
Regards Gerben