read only permission in zabbix not enough to view history graphs

Binary package hint: zabbix-frontend-php

Using Ubuntu 8.04 server LTS and zabbix 1.4.2.

1) Create a host and an item.
2) Create a host group and put that host into it.
3) Create a user group and grant "read only" permission to that host group.
4) Create a user in that user group.
5) Login as that user.
6) Click Monitoring | Latest data. The item should be listed. Click on the "graph" link and it will display an error saying "no permission". The expected behavior is to display the graph.