When I enable multi window support menu items are automatically added for File New and for showing a tab bar.
I want to open a few different windows in my app so showing these menu items does not make sense but I can't find a way to hide or remove them.
I believe you can create an NSMenuBar in a storyboard and remove the non-default elements that you don't want.
As far as I can tell these menu items are added at runtime when multiwindow support is enabled.
I actually moved away from having the menu on the storyboard. Then I can at least replace the File->New menu with my own using
func replace(menu replacedIdentifier: UIMenu.Identifier, with replacementMenu: UIMenuI am also replacing the entire View menu, but the show and hide tab bar menus also appear in the Windows menu and I don't want to hide that.
What is really needed is for UIWindow on Mac Catalyst to expose the `tabbingMode` property that NSWindow has.