@Coises said:
By default, Notepad++ runs in single instance mode. I tried it and it appears that when the Notepad++ you are attempting to open is in single instance mode, if any Notepad++ executable is open, it will switch to it instead. If you open the portable alone, with no other Notepad++ running, and change Settings | Preferences… | Multi-Instance & Date to Always in multi-instance mode, then you’ll be able to open the portable when the installed version is already running.
I think that rather than mucking with the settings that you already have set the way you want in your main N++, to run a portable alongside it is as simple as adding the -multiInst command line parameter to the invocation of the portable.