You come at a certain point in the development of every app that what you see in the simulator does not match what you think should happen. Mostly these are human errors -- or at least they are in most of my cases ;-) -- but sometimes Xcode has just 'lost track', or so it seems. I've learnt that the Clean (Shift+Cmd+K) and Clean Build Folder… (Option+Shift+Command+K) menu options can show the diff

