removeTopAlignedAccessoryViewController(at:)
NOTE: you can use this method, or -removeFromParentViewController:, whichever is easier.
Declaration
func removeTopAlignedAccessoryViewController(at index: Int)See Also
Configuring accessory views
topAlignedAccessoryViewControllersbottomAlignedAccessoryViewControllersaddTopAlignedAccessoryViewController(_:)insertTopAlignedAccessoryViewController(_:at:)addBottomAlignedAccessoryViewController(_:)insertBottomAlignedAccessoryViewController(_:at:)removeBottomAlignedAccessoryViewController(at:)NSSplitViewItemAccessoryViewController