Custom events cannot be overriden in child blueprints

Custom events cannot be overriden in child blueprints. The add event option is no longer available so as to override a custom event that was created in the parent.

This appears to be a regression. Worked in 4.16.2, No longer works in 4.17 preview 2

1. Open the editor
2. Create a new actor blueprint
3. Add a custom event to the event graph
4. Save and compile
5. Right click the actor in the content browser > Create a child
6. Open child
7. In the event graph > Right click > Search for the custom event that was created in the parent

Result: There is no option to "Add Event" as there was in the previous version. The user only has access to "Call function"
Expected: The user would be able to override the event in the child as was available in previous versions of the engine