Steps to reproduce:
1. Create a new project
2. Set layout to default
3. Turn on VR in Player settings
4. Enter Playmode
5. Select the Scene Window

Expected result: view continues as normal
Actual result: view turns into a square box surrounded by a black background

Reproduced on: 5.3.7p3, 5.4.4p3, 5.5.1p4, 5.6.0b8

Workaround: have a layout where scene and game view are split