Dismiss notifications for messages already read on another device
With multiple devices connected to a single XMPP account, Chatty's notifications become quite tiresome.
Modern XMPP clients usually provide enough information to figure out that a message has been already read on another device (XEP-0333 + XEP-0280) so it can dismiss the notification. As a good workaround for cases where Chat Markers aren't provided, Chatty could also dismiss the notification for a conversation when another client already replied to that message.