setSearchDisplayController considered private-API?

Question

I recently submitted an app for app review but I got rejected because of the use of a private API. I\'m still a bit new to iPhone developing so I was wondering if someone could

Answer 1

[self performSelector:@selector(setSearchDisplayController:) withObject:searchDisplayController];

Is a private API call and it can cause an app rejection by Apple, I know because it happened to an app I'm working on.