Just curious, what changes do you do in your external editor?
Key mapping. I have different key mapping in the text editor I have been using for years and kinda habituated to them.
Script. I have different text manipulation scripts for various task I need.
Template text. To insert quickly predefined text.
and more
In sort to do the coding quickly in more familiar environment. Nothing against B4A ide but some features which I have habit of using.
Since we already have the external editor option for files, we can extend the same for modules too.
(I also do same for my VS C# projects, opening quickly in text editor when I need it)