if you delete a hostgroup which is still referenced in an action, that action
is no longer shown in the GUI but is still stored in the DB (1.6) or the action
is shown in the GUI but with an error message (1.4.5).
This or a similar bug seems to be present in all Versions of ZABBIX.
See this thread for a description for other versions.
Will that be fixed in 1.6.1 ?
Will there be a 1.4.7 for fixing it ?