Show the connection status instead of just providing an error message
When the client goes offline, which is common when laptops suspend or for corporate implementations where a VPN is required to access the server, the only feedback provided is that the server can't be reached and to get help. This is not only not an appropriate message in this case but the message stays on the screen even after the connection is re-established. Instead of showing a disconnection message I propose replacing it with a connection state indicator. Ideally when the client is offline it will obvious (like changing the color of the window) but I won't be able to send new messages and it will also be obvious when it goes back online.