macOS NSTabViewController centered tab icons

Question

I have a macOS app I have created. And I have a Preferences window built using a swift & storyboard with a tabless Toolbar styled NSTabViewController.

I see no way to override the positioning of the tab icons though - they default to the left side of the window. Is it possible?

Answer 1

Subclass NSTabViewController and override func toolbarDefaultItemIdentifiers(_ toolbar: NSToolbar) -> [NSToolbarItem.Identifier]. Add a flexibleSpace toolbar item at both sides.