CopperEgg will automatically record an alert in your timeline as an annotation. This is an option in any alert.
The corresponding time of the alert will be shaded in a light yellow in your timeline graphs. If you click on the any particular annotation, the corresponding timeline will be highlighted in a darker yellow.
This feature will help you better correlate alerts to time frames and easily see events in the past. To enable this feature, be sure the Auto-annotate option is checked for any alert.