title: OSX WebView very slow and laggy
body: <p>I want to make a simple full screen agar.io OS X app (no title, just the game), using a WebView that loads the agar.io website... but it encounter sever lag problem comparing to Safari which is OK ... such as the game is unplayable.</p>
  
  <p>For this, I have create an simple cocoa app without storyboards (I tried with Xcode 6.4 and 7 beta, on Yosemite on a latest MacBook Pro with the best graphic card), add a webview to the window, connected the webview outlet. Here is my code :</p>
  
  <pre><code>//  AppDelegate.swift
  
  import Cocoa
  import WebKit
  
  @NSApplicationMain
  class AppDelegate: NSObject, NSApplicationDelegate {
  
      @IBOutlet weak var window: NSWindow!
  
      @IBOutlet weak var webView: WebView!
  
      func applicationDidFinishLaunching(aNotification: NSNotification) {
          // Insert code here to initialize your application
          let frame = NSScreen.mainScreen()?.frame
          window.setFrame(frame!, display: true)
          let url = NSURL(string : "http://www.agar.io")
          let request = NSURLRequest(URL: url!)
          webView.mainFrame.loadRequest(request)
          window.contentView = webView
  
      }
  
      func applicationWillTerminate(aNotification: NSNotification) {
          // Insert code here to tear down your application
      }
  
  
  }
  </code></pre>
  
  <p>Maybe I'm missing something ? </p>