Perhaps you can figure out an easy way to create a session file that has the files you want to edit, then use the -opensession command line option to open them as a session in a new instance.

An idea for a workaround: open just 1 (or a few) of the files from the explorer context menu; once that instance of NPP is open for you, drag the rest into Notepad++. I tried that with my multi-instance, and all ~1000 went into the same instance when one was context menu opened, and then the remaining that were dragged in also went in that same instance.

Other than that, the problem is on the Windows side, and (AFAIK) there’s nothing a multi-instance Notepad++ can do about it: it cannot know that in circumstance X, that you want multiple runnings of notepad++.exe to open in multiple instances, but in circumstance W, you want multiple runnings of notepad++.exe to open in a single instance. Maybe you’ll come up with some creative alternative. Good luck.

so now what… we need some kind of workaround for this sort of windows behavior of…

Sounds like it…and when you come up with it, please post it here so others can benefit.

however i still wouldnt want to keep the mono setting enabled in np++ permanently, because i do want multiple instances when i actually call np++ multiple times with different (groups of) files.

so now what… we need some kind of workaround for this sort of windows behavior of splitting that many arguments into separate calls to application.

If you opened them en masse from the explorer context menu, you probably hit a limit as to the number (or total length?) of arguments that Windows is willing to pass to the executable, and it probably then split it into a few separate runs of notepad++.exe, each with a subset of the total list of files. If you don’t have Settings > Preferences > Multi-Instance > Default (mono-instance), that would result in a separate instance of Notepad++ for every time that Windows called notepad++.

When I opened the 1024 en masse from explorer context (with mono-instance), they seemed to appear in chunks… so I think that was Windows calling notepad++.exe multiple times. But it did eventually open them all in the single instance.

If I switch to multiple-instance mode, Windows ran notepad++.exe with about 20-40 files in each instance.

Thus, if you want to be able to ExplorerContextMenu-open hundreds of files into a single instance of Notepad++, you need to have mono-instance option selected – it’s Windows calling notepad++.exe multiple times that’s the culprit, and the mono-instance just insures that no matter how many times Windows calls the executable, only one Notepad++ window will be opened.

however original question still remains i think, why hardcode a (low) limit of tabs for a single instance of np++? why i cant open all in one if they are just small text files and i have plenty of RAM, and its a 64bit app?

Don’t know, but maybe change your approach: Try the Replace in Files function…with that you don’t have to have the files to affect open in Notepad++.