Another issue: You absolutely must run Notepad++ as Administrator to make file associations work. While it would technically be possible to register associations for the current user only, which does not require more privileges, Notepad++ does not seem to make use of this. Instead, the associations silently fail if added as normal user.
Notepad++ is already able to detect whether it’s run with Administrator privileges (look at the title bar). So it should either lock down these settings (and offer restarting as Admin) or allow setting per-user associations correctly.
It took me a web search to figure that out. When documentation does not exist, the product itself must be intuitive instead.
