<t>I found a solution that seems to work. There is a cross symbol in the upper left corner of the 3D view. Left click and holding down on the top of the cross zooms in on the 3D display. I don't know if this is supposed to happen but it returned my display to the proper size. I tried the FAQ ...

My 3D image, for an unknown reason, suddenly got very small, about 1/4th of its previous size. How do I zoom in the image to get it back to full size?
Thanks in advance