title: UIButton.setTitle | Huge delay when changing the title
body: <p>I have a UIButton and when I use the « setTitle » method it takes from 1 to 20 seconds to actually change the title in my UI. </p>
  
  <p>The action is called from an async server request (when it succeed). </p>
  
  <p>And the most annoying thing is that I also used an « addAction » method on the button and this one is applying instantly.</p>
  
  <p>My button is in a TableViewCell so basically it looks like that :</p>
  
  <pre><code>override func viewDidLoad() {
      super.viewDidLoad()
  
      boolAlready = false
  
      findParticipation()
  }
  
  func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -&gt; UITableViewCell {
      let cellActions = tableView.dequeueReusableCellWithIdentifier(informationsCellArray[indexPath.row], forIndexPath: indexPath) as! eventDetailsActions
  
      if boolAlready {
          cellActions.btnParticipate.setTitle("Annuler", forState: UIControlState.Normal)
          cellActions.btnParticipate.addTarget(self, action: "deleteParticipation", forControlEvents: .TouchUpInside)
  
      } else {
          cellActions.btnParticipate.setTitle("...", forState: UIControlState.Normal)
  
  }
  
  func findParticipation() {
      //serverRequest when success :
      boolAlready = true
      print(« ok »)
      self.tableView.reloadData()
  }
  </code></pre>
  
  <p>I really don’t understand, as soon as I get the « print(« ok ») » I can press the button and it launches my target as intended. but the title remains « … » for up to 20 seconds and changes afterwards.</p>
  
  <p>I've tried to do it in the main thread by putting <code>dispatch_async(dispatch_get_main_queue()) {}</code> around my code, but it still doesn't work.</p>