Apps may wish to allow/forbid certain extension point identifiers
in iOS-8.

For example, from the link below:

http://stackoverflow.com/questions/25911004/is-it-possible-for-an-app-to-disallow-custom-keyboard-in-ios-8

To disable custom keyboard in your app completely override the application:shouldAllowExtensionPointIdentifier:

• (BOOL)application:(UIApplication *)application shouldAllowExtensionPointIdentifier:(NSString *)extensionPointIdentifier {
  // Disallow custom keyboards
  return ![extensionPointIdentifier isEqualToString:UIApplicationKeyboardExtensionPointIdentifier];
  }

Maybe it's related to QTBUG-38184