Okay, so I'm new to Objective C, Xcode, and thus also the iPhone SDK However I'm not to new programming or OO thinking, so feel free to explain things in terms of regular SE ideas. So I've written my first little app. I use a UITabBar to flip between two screens, the main functionality of the app, and a page of preferences. Everything has worked fine, and I'm starting to get a hang of things, but here is where my understanding of what is actually going on all breaks down. On the preferences page is a button, that when pressed needs to change a label on the the first page. I have an event that captures the button press just fine, but when it goes to change the label the program crashes. I'm not great with debugging things in Xcode yet, but if I had to hazard a guess, I'd say it was some sort of scope problem? I'm 99.99% sure I have everything connected properly in IB, as I am fully able to create a button in a tab that modifies a label within the currently selected tab. It's modifying a tab that isn't currently being viewed that has me stuck. When a UITabBar is used, does only one "tab" exist at a time? This might explain it. My second thought was "I'll just store the preference state in a few variables, and upon loading the first tab, use those variables to modify the UI!". However I can't find any sort of "on tab load" event. I've searched high and low for an answer, and now I'm "giving up" and coming to you guys for help. It's always the worst when you can't find an answer to a seemingly simple problem, because that usually means it's stupid-simple.