You can now amend the predefined actions in an EAlert by calling
e_alert_add_action(). Useful for adding actions from an existing
GtkUIManager.
Call e_alert_peek_actions() to obtain a combined list of predefined
and custom actions. These will typically serve as "related" actions
for GtkButtons (cf. gtk_activatable_set_related_action()).
Also, both EShellWindow and EShellView now implement EAlertSink. Use
EShellWindow for application-wide alerts, EShellView for view-specific
alerts.