On the machine that does not work right (3090) the image is drawn correctly on its initial display. Then, if I move it in any way (with the mouse), the image displays once and then it is never seen again. It would not surprise me if a setting is causing this. I will give that option a try. FWIW, the programs work fine on a 970, 1080ti, 2070, and 3080. It is only on the 3090 that there is a problem. Also the 1080ti uses W7 and the others run W10 and are laptops except the 3090 is in a desktop machine running W10. Thanks for the suggestion.