hggrep buffer used to highlight like compilation mode

[joeheyming]

I used to be able to save the grep buffer as hggrep
Then I could run compilation-next-error and emacs would go to the next file and open it in a buffer.

The workaround I have to do is run "compilation-mode" every time I save a hggrep buffer.

I looked at the .el file and it looks like helm-git-grep-mode is a compilation-mode:

(define-compilation-mode helm-git-grep-mode "Helm Git Grep"

So I'm confused at what I'm missing here.