Text Editor Anywhere allows you to select any text, open it in an editor of your choice, and insert the modified text back once you're done editing. Text Editor Anywhere is available for download from https://www.listary.com/text-editor-anywhere.

I use Text Editor Anywhere whenever I work with Windows, having it configured to open gVim on a selected text when Alt + a is pressed.

The following screenshot shows what it looks like:

When I'm done writing, I save the buffer and quit gVim. Text Editor Anywhere populates the text area with the saved buffer contents.