Why does UIViewController extend under UINavigationBar, while UITableViewController doesn't?

Question

I have UITabbarController with UINavigationController in it. I have a subclass of UIView that I assign as the view of

Answer 1

Objective-C:

- (void)viewDidLoad {
    [super viewDidLoad];
    self.edgesForExtendedLayout = UIRectEdgeNone;
 }

Swift 2:

self.edgesForExtendedLayout = UIRectEdge.None

Swift 3+:

self.edgesForExtendedLayout = []