title: Pull To Refresh Jump in iOS
body: <p>When I slowly pull down to refresh, I see the UIActivityIndicator circle slowly get more complete before it starts the refresh.  Just before the circle is complete and the refresh actually triggers, the content jumps/jerks down and then the circle starts spinning.  I only notice this when I pull down slowly.</p>
  
  <p>I'm using the pull to refresh inside a scroll view called mainSV</p>
  
  <pre><code>    self.refresh = [[UIRefreshControl alloc] init];
      [self.refresh addTarget:self action:@selector(handleRefresh) forControlEvents:UIControlEventValueChanged];
      [self.mainSV addSubview:self.refresh];
  </code></pre>
  
  <p>Why does this jump/jerk happen?</p>