I would like the have the possibility to add values/information to a custom field (summary, information, info, tag, key or something like that) which can be used to show additionally information in an event which can also be used in filters or triggers.

Example use cases are:

• tag an event with a key/tag that can be used in maps/screens as a filter. For example a tag could be an application name, service name or any other identifier which can be used to show only events with this tag in a map.
• add an application name tag/key to an event so an user can see to which application/service an alert belongs to.
• simpler queries/triggers based an a tag to group similar events based on common values which can than be used in triggers?
• show custom/extra useful information in a event
• problem/resolution correlation for log/trap or other similar alerts. A unique key in combination with type problem or resolution can be used to clear problems based on known solutions.

If I think longer I can probably think of much more possible use cases for custom/additional columns/fields.

fields should a least be able to be filled by custom_parameters, zabbix-sender, logfile items, traps and probably some more collection methods.