Some time ago, I saved a Blend file with a node setup for haze. When I opened it today, all the little image screens are gone from the nodes. I tried to set up some new nodes in a new file - same problem with all nodes that should have display screens. Also, the background image is missing in the node window. Attached are two screen shots, the upper one from the past and the lower one from the same file now.
Thanks for any clues.