Section 6.5.1.1 "Simple graphs" in the Zabbix 2.0 manual (http://www.zabbix.com/documentation/2.0/manual/config/visualisation/graphs/simple) does not explain the yellow transparent area visible in simple graphs after you zoom out a certain amount (shown in the lower screenshot). I believe these show the minimum and maximum values while the green is the average, as somewhat described here: http://www.zabbix.com/documentation/1.8/manual/about/what_s_new#improved_graphs

I think it would be good if this was explained cleary in the current documentation.

(Sorry if this is a duplicate, maybe I wasn't searching hard enough)