I'm unable to change the Interface Builder Document version to Xcode 10.0 for my existing storyboards. It always revert back to Xcode 9.0 after selecting Xcode 10.0, Save and Close when prompt, and re-opening my storyboards. Even when creating new storyboards it defaults to Xcode 9.0
Is there a way to make Xcode 10.0 my default?
Thank you in advance.