title: ios 9 - tableview cell jumps when scrolling down/up when calling cellForRowAtIndexPath
body: <p>Dear fellow programmers,</p>
  
  <p>I've recently updated to Xcode 7 and Swift 2 and now, whenever I'm scrolling down or up , the screen jumps a little bit (nothing too crazy) but it makes it the navigation laggy.
  It happens whenever I'm displaying a new cell on the screen when <strong>cellForRowAtIndexPath</strong> is called.</p>
  
  <p>In <strong>cellForRowAtIndexPath</strong>, for each Cell I'm actually setting a bunch of imageView using HanekeSwift, Labels and Buttons (using switch, case, if, etc...).</p>
  
  <p>The weird part is that whenever I comment most of those settings in <strong>cellForRowAtIndexPath</strong>, the jumpy part is gone.</p>
  
  <p>I've tried commenting each part but I haven't managed to detect what is responsible for the jump part. Or I was wondering if it could be related to  the fact that there's a lot of treatment.</p>
  
  <p>Each Cell's height is different and I'm using autolayout to detect the height for each Cell.
  timelineTableView.rowHeight = UITableViewAutomaticDimension
  timelineTableView.estimatedRowHeight = 600</p>
  
  <p>I've also tried to implement estimatedHeightForRowAtIndexPath delegate method and calculate manually the height of each Cell but without success.</p>
  
  <p>Anyone has an idea why I'm experiencing the jumpy part and why when I comment everything out, the jump is gone?</p>
  
  <p><strong>UPDATE 1 :</strong>
  while playing with Time Profiler (commenting out some functions in my cellForRowAtIndexPath method), I realize that when the running time of cellForRowAtIndexPath is lower than 80-90ms, I don't see the jumpy part. Also the higher the running time is, the more I feel the jumps</p>