Include all Fields by default to Notification template

Current it appears that we must specify fields under "Event Fields" that also must be selected for aggregation to get messages to show up in a template example:
Source: ${event.fields.source}
IP: ${event.fields.IpAddress}
Username: ${event.fields.TargetUsername}

Instead of having to specify, please allow all fields to pass through so even when filter match is selected the fields are available for alerting.