iPhone sdk 3.2.3 upgrade Problem

I just upgraded my Mac to Snow Leopard, and installed Xcode 3.2.3.

The app I am working on ran perfectly before the upgrade.

Now, the default image appears briefly, then the screen goes black except for the status bar. Same behavior on my iPhone 4 and in the simulator, whether I target iOS 3.2 or 4.

The app is still running and I an see from traces and in th开发者_开发百科e debugger that the app is running normally, and my root view controller has been loaded, but nothing but blackness on screen

Anyone seen this before?

Thanks

JK

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Problem solved. I needed to add [window makeKeyAndVisible]; to my applicationDidLaunch method. Wonder why it worked before, with just the wired up XIB file???