In the source window, you can load, create, edit, and save FORTH source files.

From here you can also send (upload) source files  to the MCU.

OBS: Source files can be nested with the INCLUDE directive. There is a separate page descriping this handy feature.

You can send the whole source file, or mark selected text in the file, and send the selected text only.

There is a search facility - usable if you are dealing with bigger source files.

You can change font, colors, font size to your liking.