I had the same problem and fixed it, but you aren't going to like the answer: I bought a new MacBook Pro. My old machine was hopeless for Xcode 15 and the iOS 17 simulators. A new macOS hello world app built and ran just fine. It was fast. Any new iOS hello world app would not work on any simulator at all (or occasionally work after more than an hour). It would work on my attached iPhone 11, but that was very slow, too. I never got my larger self-developed iOS apps working anywhere. My old computer is an earlier 2017 iMac with 16 GB memory and a 1 TB disk (500 GB free). While some of the 2017 iMacs are on the Sonoma approved list, mine was not so I was stuck with Ventura. I had tried just about everything including totally reinstalling Xcode and installing Xcode 14 and its older simulators. Nothing I tried could get me back to my workable, but slow, Xcode development environment I had a few months ago. So, is the problem: -new Xcode? -new Simulators? -old OS? -Intel processors? My new MacBook Pro is a 16-inch M3 Pro processor, 18 GB memory and a 512 GB disk (240 GB free). It's the smallest and cheapest 16-inch M3 MacBook Pro. I used Migration Assistant to move my files from the iMac to the MacBook (after doing extensive file clean up). The new machine is fast, flawless, and I like it. How many years will it be before I have to do it again?

20 seconds after I posted this, I saw my error. The line for "nnextY" has "points.y". That should be point.y. Sigh. It works now. Sorry for the wasted bandwidth. (Although the compiler could have pointed out the problem, don't you think?)

I was able to restore the Sidebar in the app by adding a third Text object in the navigation view and building and running the app. import SwiftUI struct ContentView: View {     var body: some View {         NavigationView {         Text("Sidebar")         Text("Content")             .padding() Text("More content")         }     } } Then stop the app, delete the third Text object, rebuild and run the app, and I am back to the original default settings. However, if I ever drag the boundary between Sidebar and Content too far to the left, it will disappear forever until I repeat this "fix". It sure would be nice to have a programmatic way to do this rather than rely on this kludge. Any help, anyone?