I am trying to utilize UISplitViewController to develop my app for iPad users. Since my app has a UITabBarController as its root view controller, I want to set this root view controller as a primary view controller in new UISplitViewController hierarchy, and its detail view controller to the secondary column. Also, when the app's width size class is compact (iPad SplitView mode), I want it to be same as current app. So the root view controller (UITabBarController) should be on the compact column of the new UISplitViewController system like below. class MySplitViewController: UISplitViewController { override init(style: UISplitViewController.Style) { super.init(style: style) let primaryVC = PrimaryViewController() let secondaryVC = SecondaryViewController() setViewController(primaryVC, for: .primary) setViewController(secondaryVC, for: .secondary) setViewController(primaryVC, for: .compact) } } With this code, in regular width mode, the primary and secondary column looks great as I e