Well, fixed it. Here's the whole story.
Win10 on brand new machine that had never seen LMS so went with the LMS
7.9 as stated in OP.
Couldn't change "double click" to "open web control" regardless of "run
as admin" state when control panel opened.
Downgraded to 7.8.
Set "double click" to "open
Running LMS 7.9.0 - 1472021444 on Windows 10. Open Control Panel as
Administrator. Select "Open Web Remote Control on doubleclicking the
tray icon". Doesn't stick. Is there another way to make double clicking
the tray icon open the LMS Web page rather than the LMS control panel?
2 Duets - 1