Treat system errors as other messages
I have choosen 'Show new events only in roster' option in preferences. This, in nutshell, means 'I want to control when to respond to messages, please do not bug me with popups'.
This works fine with ordinary messages, but not with authorization requests or transport-level errors: they interrupt my current work, stealing focus from the window I working with and popping up window I did not request, which is very disturbing.
I propose to pop up all messages in the manner which is used for ordinary messages: just add 'new message' mark to the roster and popup all the 'connection lost' or 'foobar requires authorization' dialogs when user explicitly asks to do it, either clicking roster or using gajim-remote.