Expected behavior
An option to hide away new notifications in a single item.
When a new invitation arrives, the invitation item is pushed to the top of the list, and clicking on it you can see the current pending invitations (and perhaps also the past declined invitation if you ever refused by mistake)
Actual behavior
Each invitation takes one line. On my mailbox, it seems I can receive dozens of mails categorized as invitations per day and it hides away any chat that I can have.