Reconnect or Try again button in balloon notification
Notification button Connection Failed is redundant and does not do anything meaningful.
An example for a balloon notification with
||'''Connection to proxy failed''' \\ Run out of hosts for name gajim.org:5223. \\ Error for last IP: Connection refused|| |||| [Connection Failed]||
It would be comfortable to click on a balloon notification button to reconnect rather than opening or just focusing attention on roster and reconnect from roster (Right-click > Status > Available).
Turn and rename Connection Failed button into _Reconnect button.