No, it's provably not true that "Scintilla only provides the textarea control that can perform syntax highlighting." So what actually loads and saves the files

No, it's provably not true that "Scintilla only provides the textarea control that can perform syntax highlighting." So what actually loads and saves the files, even if they are many megabytes? Scintilla. What is what makes that loading fast, compared to the implementation of Windows Notepad (which is how people discovered Notepad++)? Scintilla. What performs all the editing operations fast? Scintilla. What maintains all the undo information? Scintilla. What performs all the rendering of everything shown, in all the fonts and with all the configured properties, (and it works on all platforms, which is far from trivial)? Scintilla. And yes, what does all syntax coloring for all the languages? Scintilla. It's in its source base: https://sourceforge.net/p/scintilla/code/ci/default/tree/lexers/ https://sourceforge.net/p/scintilla/code/ci/default/tree/lex... Scintilla does provide all the programming level interfaces for its configuration, which can be also seen in the sources. In Notepad++, the dialogs which use these interfaces are, true, written by the Notepad++ author. So yes, most of the main functionality of the editor is in its editor engine, Scintilla, and the dialogs and menus are implemented by Notepad++.