Temporary edit with internal editor

I have configured external editors for specific file types. Works great!

Occasionally, I want to use the internal editor, temporarily, for a small number of files.
It's much faster using the internal editor than launching my entire development environment.

I would love a keyboard shortcut to once-off edit the current file(s) with the internal editor.
eg.
shift + enter = internal editor
shift + double click = internal editor
enter = external editor
double click = external editor

Or F3, borrowing from Total Commander's Lister.

Thanks for your suggestion.

This request has been added to the tracker:
https://winscp.net/tracker/827