&TLDR; I see no documentation stating that during the life of UISplitViewController, that I cannot call setViewController(xxxxx, column) more than once on the same column. Yet in my experience calling it a second time does not work, unless I set the value to nil before calling it again to set it to the new value... I'm using a UISplitViewController in newer column-style layout and when bootstrapping the app, I create the UISplitViewController and use setViewController(primaryViewController, .primary) and setViewController(detailViewController, .secondary). In order to use the primaryViewController for the compact scenario, I return the .primary column in the UISplitViewControllerDelegate method: splitViewController(_ svc: UISplitViewController, topColumnForCollapsingToProposedTopColumn proposedTopColumn: UISplitViewController.Column) -> UISplitViewController.Column Tapping a cell in the primaryViewController, results in a call to splitViewController.show(.secondary) This works for both split view (primary + secondary) as well as in compact mode. Tapping a cell in the secondary viewController results in pushing a new sub-detail onto the navigation sack. Again so far so good. If I switch back to split mode (primary+secondary) it still looks good with secondary showing the sub-detail. If I then collapse into compact view, the primary is once again shown. If I tap a different cell in the primary, the same call to: splitViewController.show(.secondary) results in the sub-detail viewController being shown. Instead, I want the secondary to show the detail for the new selected cell...not the sub-detail of the prior cell. To fix this, I popped the navigation stack for the secondary to rootViewController if secondaryNavigationController.topViewController as? DetailViewController == nil { secondaryNavigationController.popToRootViewController(animated: false) next, I attempted to replace splitViewController's secondary viewController by assigning the secondaryNavigationController which now has the DetailViewController as the top (and only) viewController. splitViewController.setViewController(secondaryNavigationController, for: .secondary) after this assignment, calling splitViewController.viewController(for: .secondary) returns the old sub-detail viewController, not the expected DetailViewController! IMO this is a bug. I found the following solution. First set it to nil, then set it to the desired value. splitViewController.setViewController(nil, for: .secondary) splitViewController.setViewController(secondaryNavigationController, for: .secondary)

My child has been learning Swift within the Swift Playgrounds but getting pretty bored with "collecting gems". I decided to purchase a Sphero RVR because it has infinite possibilities and can grow with child's coding skills. I also heard from a Sphero source that the RVR would connect and work with Swift Playgrounds. Upon unboxing I launched Swift Playgrounds, subscribed to Sphero's template and tapped "Connect to Robot". Much to my disappointment it did not find nor connect to the RVR. It does not even appear in the bluetooth discovery section of the iPad Pro. I did download Sphere's EDU app and was successful to find and connect to the Sphero RVR, however I want child to continue with Swift, not switch to block programming nor javascript just yet. Any advice to get Swift Playgrounds and Sphero RVR connected? This is a huge EDU opportunity with some cool hardware!