Meetings created in ZWC and most external systems define the time zone, for example:
Zimbra Connector for Outlook v5.0.2 with Outlook 2007 uses the time zone in the DESCRIPTION, but the DTSTART/DTEND attributes are in GMT:DTSTART;TZID="(GMT-06.00) Central Time (US & Canada)":20080229T100000
Impact:DESCRIPTION:When: Friday\, March 14\, 2008 1:30 PM-3:30 PM (GMT-06:00) Central Time (US & Canada).
The detail view in the ZWC Standard HTML renderer (only) displays the appointment time incorrectly. See Bug 25229 - Appointment detail view in HTML client (only) uses wrong time zone. Note in the picture at http://bugzilla.zimbra.com/attachment.cgi?id=9062 that the "Fax Server Group" time is correct in the day view and in the appointment body, but is wrong in the individual item's Date: header. The ZWC HTML rendering bug is triggered by any invite created by ZCO and affects the Standard HTML client, the XHTML iPhone client, and the /home/user/Calendar.html view.
1) ZCO should set a time zone for DTSTART/DTEND, not just DESCRIPTION.
2) Fix for the bug in the HTML renderer.