 		
 		activityViewController.popoverPresentationController?.barButtonItem = detailViewController.actionBarButtonItem
 		detailViewController.present(activityViewController, animated: true)
-	}
-	
-}
-
-// MARK: UINavigationControllerDelegate
-
-extension AppCoordinator: UINavigationControllerDelegate {
-
-	func navigationController(_ navigationController: UINavigationController, didShow viewController: UIViewController, animated: Bool) {
-		if rootSplitViewController.isCollapsed != true && navigationController.viewControllers.count == 1 {
-			let systemMessageViewController = UIStoryboard.main.instantiateController(ofType: SystemMessageViewController.self)
-			let showBackButton = rootSplitViewController.displayMode != .allVisible
-			let controller = addNavControllerIfNecessary(systemMessageViewController, split: rootSplitViewController, showBackButton: showBackButton)
-			rootSplitViewController.showDetailViewController(controller, sender: self)
-		}
 	}
 	
 }

			navControllerForTimeline().pushViewController(masterTimelineViewController!, animated: true)
		}
		
		if isThreePanelMode {
			let systemMessageViewController = UIStoryboard.main.instantiateController(ofType: SystemMessageViewController.self)
			let targetSplitController = targetSplitForDetail()
			let controller = addNavControllerIfNecessary(systemMessageViewController, split: targetSplitController, showBackButton: false)
			targetSplitController.showDetailViewController(controller, sender: self)
		}
	}
	
	func selectArticle(_ indexPath: IndexPath) {
		if detailViewController != nil {
			currentArticleIndexPath = indexPath
		} else {
			let targetSplit = targetSplitForDetail()

			let detailViewController = UIStoryboard.main.instantiateController(ofType: DetailViewController.self)

		rootSplitViewController.delegate = self
		
		masterNavigationController = (rootSplitViewController.viewControllers.first as! UINavigationController)
		masterFeedViewController = UIStoryboard.main.instantiateController(ofType: MasterFeedViewController.self)
		masterFeedViewController.coordinator = self
		masterNavigationController.pushViewController(masterFeedViewController, animated: false)
