Done :-)
I've seen that, that's reactive, thanks!
Reading the doc 2.1 right now, TXTWINDOW example is "TXTWINDOW 0,20,79,29" but this causes "Illegal function call" error, since cols/rows are base 1, I guess it should be "TXTWINDOW 1,21,80,30". And on Windows, Files,W/Dir,W adds an extra new line at the end of each line (and I've learned it's not a good idea to run DIR,S on the root folder of a drive containing several hundred thousands of files since it can't be interrupted...)