This OS already has an older text editor, but its fairly minimalist and simple.  I needed a new text editor with more features.  Here's what I've got so far:

So far I've got edit history for undo/redo, and the basic editing features that a text editor needs.  The font needs some work, and this program also needs to be finished (I can save but not exit XD), but at this point the program actually seems practical to use.  In fact, I used it to write some plans this morning, just as a good test.  And now I have notes stored on my Teensy 4.1 computer :P

For graphics I'm using the #RA8875 VGA card I built, which for the mostpart, is doing the job well.  This is certainly a much nicer and larger screen than I've been used to with Arduino-baded computers I built in the past. The source code is available on my gitlab server:  https://git.nuclaer-servers.com/Nuclaer/teensy-ntios/-/tree/master/src (check the editor.cpp and editor.h files)

This text editor will be an optional addition to the OS, as it requires much more features that make it take up a lot more space in code; a lot of applications don't need such a program.  Of course, for actually using a computer and administrating it, a decent text editor is critical.