In almost every other editor, at least in my experience, and several programming languages, one uses
\1 to denote a capture group insertion into a replacement string.
$1 style. While this certainly works, it seems a bit confusing, particularly if atom is trying to be an everything editor.
It also leads to some ugly replacement strings, say, for changing
$whatever. In Sublime, Ruby, TextMate, etc, I would use
$\1 as the replace string. In atom, I have to use
$$ to escape
$ and then the third to handle
\$$1, and that does not work.