This is a very simple exersize and a perfect opportunity to
get familliar with the glade-3 core :)

Basicly we need to detect semi-critical and critical errors
by marking them as they happpen and then display them in a
dialog after we've completely initialized.

I was thinking we could use g_log() with our own special
log domain[s] to mark and report critical and semi-critical
errors, even possibly success messages and then we can
use g_log_set_handler() to collect *all* messages (including
the ones reported by the underlying gtk+ and glib) and
display them in a dialog if any critical errors or
important warnings occurred, Glade-3 critical stuff would be
in red, Glade-3 semi-critical in orange and success messages
would be green, all the other messages would remain the default
black or grey but would still provide context for debugging.