two different handlers, but calling it twice with the
same event name assigns only one handler.
+Current target is temporarily overridden to the event issuing target
+before handler code starts and switched back after handler is done.
+
@item @code{-work-area-backup} (@option{0}|@option{1}) -- says
whether the work area gets backed up; by default,
@emph{it is not backed up.}