Thanks for the comeback UNI.
Was using NP++ ver 18.104.22.168. I posted on the NP++ forum, but there is not much traffic there.
Further investigation, Another computer with an earlier version of NP++, the files are visible just fine. I will try ver 6 later and post results back. Was really disconcerting though. Looks like the program uses a Windows Explorer standard frame to navigate to the file-open area. And I did not realize that there was much flexibility in what Explorer shows.