title: CADisplayLink OpenGL rendering breaks UIScrollView behaviour
body: <p>There are a few similar questions out there on SO (links at end), but none of them has allowed me to fix my problem, so here goes:</p>
  
  <p>I'm using OpenGL rendering to make an image tiling and caching library for use in a game project, and I want to hijack the physics of the UIScrollView to allow the user to navigate around the images (since it has nice bounce behaviour, might as well use it). So I have a UIScrollView which I'm using to get the rendering view for my textures, but there's a problem - moving around on the scroll view prevents the CADisplayLink from firing until the user has finished scrolling (which looks horrible). One temporary fix has been to use NSRunLoopCommonModes instead of the default run mode, but unfortunately this breaks some aspects of scroll view behaviour on certain phones I'm testing on (the 3GS and simulator seem to work fine, while the iPhone4 and the 3G don't).</p>
  
  <p>Does anyone know how I could get around this clash between the CADisplayLink and the UIScrollView, or know how to fix the UIScrollView working in other run modes? Thanks in advance :)</p>
  
  <p>Promised links to similar questions:
  <a href="https://stackoverflow.com/questions/4135229/uiscrollview-broken-and-halts-scrolling-with-opengl-rendering-related-cadisplayl">UIScrollView broken and halts scrolling with OpenGL rendering (related CADisplayLink, NSRunLoop)</a></p>
  
  <p><a href="https://stackoverflow.com/questions/4876488/animation-in-opengl-es-view-freezes-when-uiscrollview-is-dragged-on-iphone">Animation in OpenGL ES view freezes when UIScrollView is dragged on iPhone</a></p>