title: How does the view redraw itself when I disable/enable a button?
body: <p>If I enable/disable a button…what method would get called on the view?</p>
  
  <p>I’ve already placed a breakpoint on the <code>layoutSubviews</code> and don’t see it reaching there. Nor it reaches us to the viewController's <code>viewWillLayoutSubviews</code>. So I'm just curious to know how it works and what method it triggers</p>