XP was updated this morning to b3. FI now has a 'mask layer' created when XP loads and persists throughout the flight. I will try to describe it.
If I am looking straight forward in the cockpit when XP loads the mask is exactly the same size and shape as the windshield. If I hold the Vive up above the fuselage and start up XP it is like a Photoshop mask layer of the scenery the headset is pointing to.
Up in the air, and in heavy clouds, if I position the 'mask' by moving my head to look down to earth, I can clearly see the ground through the 'mask' but the clouds are not rendered on the 'mask'.