FieldEventHandler.Action just duplicates
EventHandler.Action without adding any field specific behavior or information. Remove the duplicate enum and just use
EventHandler.Action. It may be worth moving
Action to a top level type to clarify it can be used for field and non-field event detectors. Hipparchus only uses one Action enum for both double and Field ODEs. This change will break backward compatibility, so it should wait until the next major release.
Other option is to delete both of Orekit's Action enums and just use Action from Hipparchus since they must all define the same values for Orekit to work correctly.