On Firefox, trying the demo viewer "Try it out": If you click -particularly on a room's label, but also happens when clicking somewhere else-, everything disap

On Firefox, trying the demo viewer "Try it out": If you click -particularly on a room's label, but also happens when clicking somewhere else-, everything disappears except for the labels. If you click again, everything comes back. Sometimes when click-dragging to rotate, this produces an annoying flash -white for an instant then everything's redrawn. Also some textures seem to not be loading properly. All furniture remains black.