For the explicit 'Show in File Tree' use case, the original code worked fine as far as I'm aware... so if we're not using this for some other purpose I think leaving the original code is safest.

I do agree that double-click on a Find in Files result should add it to the working set.  Looks like this is being tracked by the [main Find in Files user story](https://trello.com/card/8-find-in-project-aka-find-in-files/4f90a6d98f77505d7940ce88/266).  (And the in-progress pull request #3151 implements it).