How to edit Python scripts in an external editor?

[raincole 2]

I'm talking about the Python scripts in an HDA:

When I press "Edit text in an external editor", it opens my editor of choice (VScode in my case):

But it's a *temp* file. When I make changes there and save it, the script in Houdini doesn't change at all!

It's definitely not how I expected "edit in an external editor" works. I googled and found this: http://cgtoolbox.com/houdini-expression-editor 

However, it only works for parameter expressions, not for scripts in HDAs.