Hi, i'm reading the excellent Apress book on Beginning IPhone Development. in their examples, they always build their interface by double-clicking the MyProgramViewController.xib. But when i tried the same and ran the Iphone Simulator later, the interface loaded from MainWindow.xib. i referred few online guides and they'd modified MainWindow.xib itself. I'm i missing something here? i havent grasped the concept entirely but i'd like to know where the file loads from? and when i should modify the ViewController.xib and when i should modify the MainWindow.xib. Hope i was clear in explaining my problem. Thanks!