Notepad++ would have been very new at that time. I don't know what those early releases were like.

But there were similar editors. I remember using SCIte which was similar to Notepad++. SCIte was first released in 1999.

Notepad++ is based on Scintilla, for which Scite is sort of the demo program. Scintilla is also the basis of Geany.

I explained this recently on the Reg. Read the Reg. ;-)

https://www.theregister.com/2023/12/06/veteran_editors_notep...

My editor of choice back in the Windows days was EditPlus, from 1998 (and looks like it's still maintained). I think it had syntax highlighting from the start too.