I have now discovered that the culprit is not HDP or Sketch Up or Windows 10. It's the plan I was working with. I have a complex house plan that I was using when I tried to import symbols into when I started having trouble with even the simplest symbols. I found that if I created new plan and imported the symbols into that one, there was no problem. I also found that if I added those symbols to the user library and returned to my complex house plan - I could use them flawlessly from that library.
This is not a solution but a work-a-round. The root cause is still a mystery. Apparently my house plan is corrupt in some way. Is there a tool or procedure that can repair a plan file?
I will mark this topic as solved only because I have side stepped my problem. I hope that it helps someone that encounters this problem. I will start looking for topics involving a corrupt plan file.
I meant that I could not do it because I could not find that dialog box. I did not mean to imply that it might not work. I am still finding my way around Pro. I did eventually find it and it did work. Thank You!
A related question. I had to edit ever room in the finished basement to fix the floor evevation that got wacked when I changed the floor height. When I selected several of them, the entry box was not accessable. Is there a trick that would have made that a bit easier?
I am now able to get on with my design. Thanks Again!