How to enable a popup sub menu when click + on the right?

See this video:

https://developer.apple.com/videos/play/wwdc2014/214/

In the video, it is explained how to use Popovers in iPhone apps.

But, if you still think you should avoid popovers, you may need to choose again.

I do not understand what you mean with What about UITextView?, it is very unlikely that `UITextView` can be an option when you want "a popup sub menu".