I posted this on Notepad++ Community. Claudia has confirmed it, and has advised me to post here. I'm using Notepad++ 6.8.8 on Windows 7 Pro SP1.

Suppose that a file Test.txt has two alternate data stream files associated with it. When I edit the file with Notepad++, and then save it (Ctrl + S), the ADS files have been removed.

This doesn’t happen with Notepad, and with UEStudio, there is a setting to prevent it.

QUESTION: How do I save a file in Notepad++ without removing the alternate data streams?