Firefox 57 compatible, very simple and straight forward, without any bloat.

Good addon, exactly what I have been waiting from a gmail checker :
- simple (no panel or any other bloat)
- open directly gmail in your inbox (and do not open your first unread message when you have one)

I'm happy with it ! :-)

What would be nice is to be able to set interval check and to choose if you want to open gmail (= https://mail.google.com/) or google inbox (= https://inbox.google.com/).

Edit : I edited my post to make clear what I meant with "google inbox"