If the -opengl4 command is used while launching the editor it will cause the viewport to go black if something in the level is selected or while using RMB to look around the level.
1. Open UE4Editor with "./UE4Editor -opengl4" command
2. Create new project
3. Once project opens, click on an object in the World Outliner or use RMB to look around
The viewport will go black as the camera pans around.
Head over to the existing Questions & Answers thread and let us know what's up.