This add on manager is however still reporting XPOI as installed in trial mode.What could be wrong here ? was not expecting to see anything about XPOI
It always said the same even if you never installed XPOI.
In Trial mode, means there's no serial number for it in the registry and, since XPOI is not a scenery, there's no check on its .BGL files (there aren't any .BGL file) to verify is NOT installed (so it won't generate bogus "trial has started" message if you fly in an area of a scenery that is not installed), so the Addon Manager assumes is installed since the check is skipped.
If you don't see the XPOI menu when you press the XPOI hotkeys, it means it has correctly uninstalled.
