title: UIScrollView broken and halts scrolling with OpenGL rendering (related CADisplayLink, NSRunLoop)
body: <p>Solution note, Not a question.</p>
  
  <p><code>UIScrollView</code> suspends OpenGL rendering by preventing firing <code>CADisplayLink</code> tick when <code>CADisplayLink</code> registered with <code>NSDefaultRunLoopMode</code>.</p>
  
  <p>But, if you use <code>NSRunLoopCommonModes</code> to solve this, <code>UIScrollView</code> will halt scrolling at burst scrolling. And after once halted, it does not scroll again. (broken)</p>
  
  <p>And registering CADisplayLink in other thread/runloop (as described in answer of this question: <a href="https://stackoverflow.com/questions/2524347/cadisplaylink-stops-updating-when-uiscrollview-scrolled/4135266#4135266">CADisplayLink stops updating when UIScrollView scrolled</a>) reduces UIScrollView behavior breaking, but cannot eliminate.</p>