If you're not familiar with Jira Events, please read the article carefully to discover full SLA PowerBox plugin potential.
A Jira Event is a message that an issue sends to all Jira background processes when a change on the issue is performed. Event, once fired, can be processed by multiple background processes (called listeners) such as email sending listener or the SLA listener.
Any change performed on a Jira issue creates a corresponding issue event. E.g. if you create an issue, an Issue Created event is fired. The Jira mechanism is dependent on the issue events. They inform the system that something has happened and trigger appropriate actions within Jira.
The two types of issue events in Jira are:
System events that are fired by Jira internally. They cannot be changed or deleted but can be used by workflow designers outside of standard actions. Tip: On the Atlassian Documentation Space you can read that events can be inactivated. But regardless the event activity status it can be used in SLA Behaviours.
Custom events - are defined by system administrators and used in workflow transitions.
Events are generally sent in two major situations:
Issue Actions - a standard issues action such as editing or commenting without executing any workflow transition. Event for the Actions cannot be changed (e.g. adding a new comment always fires an event called "Issue Commented" and changing the issue's assignee through the "Assign" button always fires an event "Issue Assigned").
Workflow Transitions - each workflow transition fires an event. When you design your workflow you have to set it up (usually it's the very last post function in each transition) or use a standard event proposed by Jira. Normally JIRA proposes the "Issue Created" event for Create transition and "Generic Event" for the rest. We strongly recommend using your own transition for each event especially in large JIRA instances (due to possible performance improvements).
It's possible to assign Jira System events to workflow transitions (e.g. the "Issue updated" event can be fired both on the Edit issue action and on a workflow transition). If you want to treat it differently in your SLA, use an Action parameter.