How to hide stacked navigation bars when using SwiftUI inspector in UISplitViewController secondary column

During WWDC Q&As I asked how I could add an inspector to my UIKit app that’s using UISplitViewController with a double column style featuring a sidebar and detail view controller. I initially tried a full-height inspector (by putting my split view controller into a SwiftUI view and applying the inspector on that, embedding that into a UIHostingController to be the rootViewController) but this caused a bunch of UI bugs (seemingly related to optimizations made for a size class that doesn’t match the actual appearance) and it doesn’t extend into the NSToolbar on Mac Catalyst anyways. I now want to try implementing the under-the-toolbar solution. An engineer said:

For an under toolbar appearance, you should be able to use .inspector on the detail view controller (after wrapping it in a SwiftUI view), but you may have to do manual toolbar management here (hiding and showing) to make sure you don't end up with stacked toolbars/UINavigationBars

I have indeed run into the problem with two navigation bars in my inspector. I want to keep the navigation bar visible in the detail screen, but I do not want any navigation bars visible in my inspector since I’m going to provide my own button to toggle the inspector (via a button in the detail on iOS and an NSToolbarItem on macOS). Is this layout possible? I tried applying .toolbar(.hidden) on the inspector’s view but this doesn’t do anything, there’s still two stacked navigation bars (tested on iPadOS 17 beta 2). I think even if that worked it would only hide the inner navigation bar, I’d still have an undesirable navigation bar. :/ Wishing there were a UIKit API I could avoid the interop complexity ha

In the sample project attached to FB12447791, the root view controller is a UISplitViewController. The primary view controller is a UINavigationController containing a sidebar. The secondary view controller is a UINavigationController containing a UIHostingController whose root view is a SecondaryColumnView. SecondaryColumnView is a Form that has a button to Toggle Inspector, a navigation title, and an inspector. The inspector is a Form that has .toolbar(.hidden).

I've provided several screen recordings in the feedback report as well. Thanks for your help and insight!

How to hide stacked navigation bars when using SwiftUI inspector in UISplitViewController secondary column
 
 
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