title: Why does Xcode keep recompiling my untouched project?
body: <p>I have an Xcode 4 workspace with several projects. Everything builds perfectly and works as expected, only Xcode recompiles files too often. If I hit the Build button, wait for the compilation to succeed and then hit the button again, shouldn’t that be essentialy a no-op, since no files have changed? Because my Xcode recompiles a big part of the project again. Even when I build and then immediately hit the Play button, I have to stare at the building process again. Is that neccessary, is it expected behaviour?</p>