title: cocoa - Unexpected outstanding background CATransaction
body: <p>I am developing a macOS application using cocoa.</p>
  
  <p>I have a NSScrollView instance called scrollView and a custom view instance called customView, and I use</p>
  
  <pre><code>[scrollView setDocumentView:customView];
  </code></pre>
  
  <p>in my AppDelegate's <code>applicationDidFinishLaunching:</code> method.</p>
  
  <p>But when I run this application, and use my track pad to scroll, the application crushes, the Xcode turns to the threads part and displays "libsystem_kernel.dylib`__pthread_kill:" and the instruction that fails is jae.</p>
  
  <p>The console displays "Unexpected outstanding background CATransaction".</p>
  
  <p>But!!! When I click the scroller of the NSScrollView and drags it, the application doesn't crush.</p>
  
  <p>It is so strange and I have no way to solve it.</p>