Shaded View showing wireframe - no blue selection highlight

[3dway]

After using the wall joint tool, my model fails to display shaded mode correctly.
It looks, sort of, like a bit of wireframe showing through. The blue highlights also stop.

Is this a known issue?
Search of topics here turned up too many results; none of which looked like the topic.

[scourdx]

Sounds like a graphic driver issue. Try updating your video card driver.