title: Virtualbox on a MacBook Pro causes black screen on resolutions bigger than 1920 x 1080
body: <p>I have installed Virtualbox and have Ubuntu up in it. I use a Macbook pro and I installed guest extension on my Ubuntu.</p>
  
  <p>My Display has a resolution of 2560x1280 Pixels but as soon as I scale the Virtualbox screen bigger than FullHD the ubuntu shows a black screen.</p>
  
  <p>Any ideas?</p>