On the upper left of Xcode 4 you can select a scheme and a simulator to use for that scheme.

I have 2 questions about this:
-
You see here that the simulator to use for this scheme is “My Mac 64-bit.” This is actually a copy of another project I made. In the original project, I could select 3 simulators for this scheme: the iPad 5.1 simulator, the iPhone 5.1 simulator, or simulate on my actual phone. I then duplicated the whole project directory, opened up the duplicate Xcode project file, and the only option for a simulator is “My Mac 64-bit.” This is an exact duplicate, and yet the simulator options are different. Why?
-
For schemes that show those 3 options I mentioned for simulators, I can also click “More Simulators” and there the iOS 4.3 simulator can be downloaded and installed. So I did that, but the iOS 4.3 simulator is still not showing in the list of simulators that I can use. There’s no point in downloading and installing it if I can’t even use it. How can I make this show in that list of available simulators?
Something may have changed in your build settings, check to make sure your base SDK is set to iOS.