Create a shared OpenGL context in GearVR on Android

I am writing a plugin that needs to create a shared OpenGL context with Unity. That works perfectly fine for Unity apps as well as for Google Cardboard apps. As soon as I activate "Virtual Reality Supported" it fails to write to the texture.

Is there anything special to support shared context with "Virtual Reality Supported"? When is the VR context created, does it work with native plugins?