title: Unreal Engine 4.20.1 VR Preview Greyed Out
body: <p>As title says, the VR Preview option from the play menu is greyed out. I am using the Vive Pro and SteamVR.</p>
  
  <p>Things I have checked:</p>
  
  <ul>
  <li>Vive Pro devices' firmware are all updated.</li>
  <li>I am using SteamVR beta and it is updated.</li>
  <li>I made sure the Vive Pro were connected by testing them in SteamVR Home.</li>
  <li>I have disabled SteamVR Home before launching Unreal Engine</li>
  <li>I have tried both the UE4's VR template and a empty game (Blank template, 
  Mobile, Scalable, No Starter Content).</li>
  <li>I have double checked that the SteamVR plugin is enabled.</li>
  <li>SteamVR window says Ready and all 5 devices are green.</li>
  </ul>
  
  <p>Computer Specs:</p>
  
  <p>OS: Windows 10<br>
  CPU: Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz<br>
  RAM: 16GB<br>
  GPU: NVIDIA GeForce GTX 1080</p>
  
  <p>Additional notes:</p>
  
  <ul>
  <li>I have packaged the VR template and ran it. The headset does not rotate camera 
  but the controllers would still teleport me.</li>
  <li>vr.bEnable Stereo 1 does not do anything, at least visibly.</li>
  </ul>