(on Dec. 24, I wrote)
... I need to try/test this [dnfdragora] more. Now I think it's just doing whatever I last asked when I last exited. ...
I was correct. For example, if I set it to show "Groups", "Not installed", "in names", search string blank, then click "Quit", then the next time I launch the tool, even after re-boot and log in (same user), or log out - log in (same user), the tool will show all groups that are available but not installed on the workstation.
(on Dec. 23, I wrote)
... Consider this thread in a "beta" state for a few days to make sure there are no problems. ...
Beta testing done. After a weekly patching, a few cycles of nightly power-down and morning power-up, and a few days of regular operational use, I'm confident this really is fixed. I'm upgrading this to SOLVED. I thank participants for their help.