I'll try this way in a few moments.

splitVC.preferredSplitBehavior = UISplitViewControllerSplitBehaviorTile; splitVC.preferredDisplayMode = UISplitViewControllerDisplayModeOneBesideSecondary; the primary view controller still overlays the secondary one. On macOS 15 / Xcode 16 this worked as expected (side-by-side), but on macOS 15 / Xcode 26 the behavior changed and the primary view now covers the secondary. This seems to be a regression or a new behavior introduced in the latest SDK.

I also encountered this issue.

I also encountered this issue. When I set: splitVC.preferredSplitBehavior = UISplitViewControllerSplitBehaviorTile; splitVC.preferredDisplayMode = UISplitViewControllerDisplayModeOneBesideSecondary; the primary view controller still overlays the secondary one. On macOS 15 / Xcode 16 this worked as expected (side-by-side), but on macOS 15 / Xcode 26 the behavior changed and the primary view now covers the secondary. This seems to be a regression or a new behavior introduced in the latest SDK.

So, what about the UINavigationBar. My navigationItems moved to top bar, maybe we should call it toolbar. Now my actions are different from what on iOS.

It works for me! Thank you.