Apps don't just rotate. You need to configure and most importantly code it so that they rotate. For example, notice that when Safari rotates, the navigation bar

Apps don't just rotate. You need to configure and most importantly code it so that they rotate. For example, notice that when Safari rotates, the navigation bar and toolbar height shrinks by half. That is done programmatically. It's not as easy as just setting a flag and the contents will rotate magically.