I have exactly the same behaviour as described by Gilles-Philippe Morin (#21).
I've made the changes suggested by Rodrigo Silva dos Santos (#23), and something seems to improved. Know the icon in the launcher opens the webpage and has the right-click-option to Compose a new mail. However, there are no indication of unread mails (neither in the launcher nor in the top menu bar).
I have exactly the same behaviour as described by Gilles-Philippe Morin (#21).
I've made the changes suggested by Rodrigo Silva dos Santos (#23), and something seems to improved. Know the icon in the launcher opens the webpage and has the right-click-option to Compose a new mail. However, there are no indication of unread mails (neither in the launcher nor in the top menu bar).