If I create a filter predicate that uses the event type, I cannot modify that predicate. E.g. if the predicate is

Event Type is com.oracle.jdk.FileRead

I cannot change "is" into anything else, and I cannot change "com.oracle.jdk.FileRead" into any other event type.

I thought this was because it was a "page filter" of some sort, but it turns out that the same applies for predicates that I bring to the table myself.