Maintaining Handler IDs through Metadata Updates

Each event handler is identified with a unique and hidden ID, which is referenced by the Keep With field on the Event Handlers form. This ID, rather than the actual Handler Sequence number, becomes the fixed reference point for that handler. An event handler owner does not need to maintain the Handler Sequence numbers across releases. The system takes care of of the number automatically, by preserving the hidden ID number and reassigning Handler Sequence numbers as required.

After each insertion, update, or deletion of a handler, and during a merge performed by the App Metadata Sync utility or the App Metadata Transport utility, the system calculates new integers, if necessary, for display in the Handler Sequence field. However, the underlying ID remains unchanged. When a handler is deactivated and another added in the same position, the new handler gets a new ID.