[fatboy]

I only half-conveyed what I was aiming to; I'm able to do what you're describing by editing the search-results scratch-file then saving it. The changes propagate to the target files with the save.

I've had a look though, and you were right: it's due to an extension that I can save from the scratch file:

https://marketplace.visualstudio.com/items?itemName=jakearl....