The default behavior of the Sublime Text 3 launcher in Windows is to show any currently open Sublime Text windows. This really shouldn’t be the default behavior, but what-evs.
My quickfix: create a new batch file named sublime-launcher.bat with the following contents:
start “C:/Program Files/Sublime Text 3/sublime_text.exe” “–new-window”
For whatever reason, I’m not able to pin this to my start bar in Windows 10. Tired of these things–so as soon as I get the time I’ll be swapping my primary installation over to some flavor of linux.